Evaluation of a satellite telemetry system for monitoring movements of caribou

A cow caribou from the Central Arctic Herd was collared with a satellite-monitored radio transmitter in the Kuparuk Oilfield, Alaska, in 1984. From 19 June to 17 August, the radio transmitted 18 hours per day. A total of 346 locations were recorded, for a mean of 5.8 locations per day or one location every 3.1 hours of transmission time. The location of 13 direct observations of the radio-collared cow averaged less than 1 km from the nearest satellite-fixed location. The satellite-fixed locations of the radio-collared cow provided detailed data on movement patterns during the three seasons studied. The cow traveled an average of 8 km day1, 23 km1, and 14 km day1 during the post-calving season, mosquito season, and oestrid fly season, respectively

A Sighting of an Albino Caribou in Alaska and Review of North American Records

An albino caribou (Rangifer tarandus granti) calf was observed among members of the Porcupine Herd on 2 July 1976 near the Kongakut River in northeastern Alaska (69° 27' N, 141° 30' W). It had snow-white fur and pink eyes. Hooves and muzzle were light-colored. The calf's behavior was similar to normally pigmented calves. This individual was the only albino observed in a group of 15,000 to 20,000 individuals. Observations were made for approximately two minutes at 300 m using a 45 power spotting scope. Eight other people observed the calf. ..

Opportunismo e coordinamento: soluzioni regolative e istituzionali

The present paper builds on Arrighetti e Curatolo, 2009, 2010 by introducing heterogeneous opportunists into an agent-based simulated world populated by heterogeneous loyal agents playing a repeated coordination game. On average, opportunistic exploitation of economic resources lowers coordination, especially in less endowed contexts. Simulation strategy proposed in the paper compares, keeping constant the aggregate cost of policy, three different kinds of public schemes aimed at reducing the economic cost of opportunism: regulatory schemes, incentive (or premiality) schemes and a third scheme based on institutional catalyst agents. Regulatory schemes based on sanctions produce the emergence of adverse redistribution effects: removal of opportunism is an efficient strategy only for less endowed local contexts, while the policy taxation burden hits too much the local environments where collective action is stronger. In line with many authors (see Hall, 2005; Camerer e Hogarth, 1999; Verdier, 2004), incentive (premiality) schemes perform badly especially because their net effects are limited to the first stages of the games. The schemes based on institutional catalyst agents seems to be the best performers: in facts, these schemes are efficient, especially through a process of learning, in pulling the other agents toward an high degree of coordination, so counter-balancing the effects of opportunists’ exploitation. Moreover an high degree of synergy emerges from a combined regulatory-institutional catalyst scheme, while incentive scheme (premiality) show, at the opposite, negative synergy both with institutional catalyst agents’ and regulatory schemes.Opportunism, Coordination Games, Regulation, Incentives, Institutions

Automatic Balancing for Satellite Simulators with Mixed Mechanical and Magnetic Actuation

Dynamic spacecraft simulators are becoming a widespread tool to enable effective on-ground verification of the attitude determination and control subsystem (ADCS). In such facilities, the on-orbit rotational dynamics shall be simulated, thereby requiring minimization of the external torques acting on the satellite mock-up. Gravity torque is often the largest among the disturbances, and an automatic procedure for balancing is usually foreseen in such facilities as it is significantly faster and more accurate than manual methods. In this note, we present an automatic balancing technique which combines mechanical and magnetic actuation by the joint use of sliding masses and magnetorquers. A feedback control is employed for in-plane balancing in which the proportional and integral actions are provided by moving the masses, while the derivative action is provided by the magnetorquers. Compared to an earlier implementation by the authors relying on shifting masses only, the novel approach is shown to reduce the in-plane unbalance by an additional 45% on average

Determinanti della domanda di laureati nell'industria manifatturiera italiana

Tertiary education attainment of italian labour force, particularly in the manufacturing industry, shows empirically a large gap with respect to the other OECD countries, although human capital growth has been increasingly addressed as one of the main channel towards productivity, competitive success and firm size growth. The paper analyses empirically four different explicative hypotheses, each with its own set of proxies: firm size, sectoral differences in human capital intensity, education supply of the labour force, and firm-specific demand issues. Estimates show that while structural explanations based on firm size and sectoral differences play a key causal role in determining the observed low level of human capital, supply conditions seem to have a lower esplicative power, both directly through local supply of educated workers and indirectly through their weight on the labour cost. Firm-specific demand variables, particularly those proxying for the complexity and richness of organizational structure and management, show instead the highest explicative power. More particularly, family-managed firms seem to perform a sort of "subjective resistance" to a more intensive employment of highly educated labour force.Human capital, Educational attainment, Labour demand, Labour supply, Graduate employment , Staff ratio, White Collars, Manufacturing industries, Firm size, Italy

Quadrupole scan emittance measurements for the ELI-NP compton gamma source

The high brightness electron LINAC of the Compton Gamma Source at the ELI Nuclear Physics facility in Roma- nia is accelerating a train of 32 bunches with a nominal total charge of 250 pC and nominal spacing of 16 ns . To achieve the design gamma flux, all the bunches along the train must have the designed Twiss parameters. Beam sizes are mea- sured with optical transition radiation monitors, allowing a quadrupole scan for Twiss parameters measurements. Since focusing the whole bunch train on the screen may lead to permanent screen damage, we investigate non-conventional scans such as scans around a maximum of the beam size or scans with a controlled minimum spot size. This paper discusses the implementation issues of such a technique in the actual machine layou

Single-injection thoracic paravertebral block for postoperative pain treatment after thoracoscopic surgery

Background. Thoracoscopic surgery can be associated with considerable postoperative pain. While the benefits of paravertebral block on pain after thoracotomy have been demonstrated, no investigations on the effects of paravertebral block on pain after thoracoscopy have been conducted. We tested the hypothesis that a single-injection thoracic paravertebral block, performed preoperatively, reduces pain scores after thoracoscopic surgery. Methods. Of 45 patients recruited, 40 completed the study. They were randomly allocated to two groups: the paravertebral group received i.v. patient-controlled analgesia (PCA) with morphine plus single-injection thoracic paravertebral block with bupivacaine 0.375% and adrenaline 1:200 000 0.4 ml kg−1 (n=20). The control group was treated with a back puncture without injection and morphine PCA (n=20). Results. The main outcomes recorded during 48 h after surgery were pain scores using the visual analogue scale (VAS, 0-100). Secondary outcomes were cumulative morphine consumption and peak expiratory flow rate (PEFR). Half an hour and 24 h after surgery, median (25th-75th percentiles) VAS on coughing in the paravertebral group was 31.0 (20.0-55.0) and 30.5 (17.5-40.0) respectively and in the control group it was 70.0 (30.0-100.0) and 50.0 (25.0-75.0) respectively. The difference between the groups over the whole observation period was statistically significant (P<0.05). Twenty-four and 48 h after surgery, median (25th-75th percentiles) cumulative morphine consumption (mg) was 49.0 (38.3-87.0) and 69.3 (38.8-118.5) respectively in the paravertebral group and 51.2 (36.0-84.1) and 78.1 (38.4-93.1) in the control group (statistically not significant). No differences were found in PEFR or the incidence of any side-effects between groups. Conclusion. We conclude that single-shot preoperative paravertebral block improves post-operative pain treatment after thoracoscopic surgery in a clinically significant fashio

A robust numerical methodology for fatigue damage evolution simulation in composites

Composite materials, like metals, are subject to fatigue effects, representing one of the main causes for component collapse in carbon fiber‐reinforced polymers. Indeed, when subject to low stress cyclic loading, carbon fiber‐reinforced polymers exhibit gradual degradation of the mechanical properties. The numerical simulation of this phenomenon, which can strongly reduce time and costs to market, can be extremely expensive in terms of computational effort since a very high number of static analyses need to be run to take into account the real damage propagation due the fatigue effects. In this paper, a novel cycle jump strategy, named Smart Cycle strategy, is introduced in the numerical model to avoid the simulation of every single cycle and save computational resources. This cycle jump strategy can be seen as an enhancement of the empirical model proposed by Shokrieh and Lessard for the evaluation of the fatigue‐induced strength and stiffness degradation. Indeed, the Smart Cycle allows quickly obtaining a preliminary assessment of the fatigue behavior of composite structures. It is based on the hypothesis that the stress redistribution, due to the fatigue‐induced gradual degradation of the material properties, can be neglected until sudden fiber and/or matrix damage is verified at element/lamina level. The numerical procedure has been implemented in the commercial finite element code ANSYS MECHANICAL, by means of Ansys Parametric Design Languages (APDL). Briefly, the Smart Cycle routine is able to predict cycles where fatigue failure criteria are likely to be satisfied and to limit the numerical simulation to these cycles where a consistent damage propagation in terms of fiber and matrix breakage is expected. The proposed numerical strategy was preliminarily validated, in the frame of this research study, on 30° fiber‐oriented unidirectional coupons subjected to tensile– tensile fatigue loading conditions. The numerical results were compared with literature experimental data in terms of number of cycles at failure for different percentage of the static strength. Lastly, in order to assess its potential in terms of computational time saving on more complex structures and different loading conditions, the proposed numerical approach was used to investigate the fatigue behavior of a cross‐ply open‐hole composite panel under tension–tension fatigue loading conditions