Discounting of reward sequences: a test of competing formal models of hyperbolic discounting

Humans are known to discount future rewards hyperbolically in time. Nevertheless, a formal recursive model of hyperbolic discounting has been elusive until recently, with the introduction of the hyperbolically discounted temporal difference (HDTD) model. Prior to that, models of learning (especially reinforcement learning) have relied on exponential discounting, which generally provides poorer fits to behavioral data. Recently, it has been shown that hyperbolic discounting can also be approximated by a summed distribution of exponentially discounted values, instantiated in the μAgents model. The HDTD model and the μAgents model differ in one key respect, namely how they treat sequences of rewards. The μAgents model is a particular implementation of a Parallel discounting model, which values sequences based on the summed value of the individual rewards whereas the HDTD model contains a non-linear interaction. To discriminate among these models, we observed how subjects discounted a sequence of three rewards, and then we tested how well each candidate model fit the subject data. The results show that the Parallel model generally provides a better fit to the human data

Temperature controlled light-emitting diode lamp for photovoltaic rural applications

In recent years, interest in light-emitting diode (LED) lighting has been growing because of its high efficacy, lifetime and ruggedness. This paper proposes a better adaptation of LED lamps to the technical requirements of photovoltaic lighting domestic systems, whose main quality criteria are reliability and that behave as voltage power supplies. As the key element of reliability in LED lamps is temperature, a solution is proposed for driving LED lamps using voltage sources, such as photovoltaic system batteries, with a control architecture based on pulse width modulation signal that regulates the current applied according to the LED lamp temperature. A prototype of the LED lamp has been implemented and tested to show its good performance at different temperatures and at different battery voltages

Preemptive Ketamine Administration

Optimal pain management for the surgical patient is challenging for anesthesia providers. Finding new and improved methods of relieving surgical pain and evolving new techniques is an area of much research. The concept of preemptive analgesia suggests that the best postoperative pain management begins preoperatively (Morgan, Mikhail, & Murray, 2009). Preemptive administration of analgesic medications is used to stop pain from starting by blocking the nervous system\u27s usual response to pain. This preemptive approach is thought to prevent wind up after the noxious stimulus of a surgical incision and can help prevent heightened sensitivity and lasting pain after surgery Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist that has undergone nwnerous studies for its preemptive administration benefits. Evidence shows that ketamine when given preemptively, intravenously or by epidural, can have a positive effect on postoperative pain. Ketamine given in small doses prior to surgical incision is shown in many studies to decrease postoperative pain, thus, decreasing narcotic requirements The information obtained from the research on this topic was presented to both student nurse anesthetists and practicing nurse anesthetists at the North Dakota Association of Nurse Anesthetists fall meeting in Bismarck, ND. Implications for anesthesia providers and students included adding a pain relief strategy to their already growing arsenal of analgesic methods. Better pain management for surgical patients can lead to less anxiety, discomfort, stress, and earlier discharge from the hospital saving healthcare dollars (Aston, 2012)

Sentencing

Once the legislature has defined the acts it will punish as criminal, it must then establish a sentencing system. There are two principal features of a sentencing system: it grades crimes according to seriousness, and it apportions sentencing discretion among the legislature, the courts, and administrative agencies. The device for apportionment between the legislature and the courts is the mandatory sentence, by which the legislature may fix a period of imprisonment for a crime and forbid judges to grant probation. Apportionment of sentencing discretion between the courts and administrative agencies, on the other hand, is governed by the choice between definite and indeterminate sentences. In a definite sentence, the trial judge fixes the period of imprisonment; an indeterminate sentence leaves the length of imprisonment open to continual reevaluation by an administrative agency. Thus, a legislature must decide how much criminal punishment to authorize, which crimes to subject to mandatory sentences, and whether to authorize definite or indeterminate sentences (or both). The Maine Legislature has made these critical choices in Part 3 of the Criminal Code

Remembrance of Professor David Gregory

The Board and Staff of the Maine Law Review dedicate this issue to the memory of Professor David Doliver Gregory, who passed away on December 9, 2000. The Maine legal community and the University of Maine School of Law mourn the loss of our beloved teacher, advocate, and friend. In the collective memory of his students, Professor Gregory will always be remembered for the Socratic genius that he employed so effectively in class; his keen wit, often accompanied by a knowing smile and a twinkle in his eyes; his passion for ferreting out seemingly elusive legal principles; and his compassion and warmth for those he instructed. Perhaps above all, Professor Gregory will be recalled as the archetypal Law Professor that he was. He was the rarest of educators, someone who taught us how to challenge ourselves intellectually, and who demonstrated both in his life and in his teaching that the law not only reaches all facets of society but also touches upon the most fundamental and important aspects of human existence itself. On January 17, 2001 hundreds of his colleagues and students gathered at the First Parish Church in Portland, Maine to celebrate Professor Gregory\u27s life. What follows are the remembrances delivered at the memorial service and two tributes from professional colleagues that give a picture of his life in the courtroom and the classroom

Seatbelt use and risk of major injuries sustained by vehicle occupants during motor-vehicle crashes: A systematic review and meta-analysis of cohort studies

BackgroundIn 2004, a World Health Report on road safety called for enforcement of measures such as seatbelt use, effective at minimizing morbidity and mortality caused by road traffic accidents. However, injuries caused by seatbelt use have also been described. Over a decade after publication of the World Health Report on road safety, this study sought to investigate the relationship between seatbelt use and major injuries in belted compared to unbelted passengers.MethodsCohort studies published in English language from 2005 to 2018 were retrieved from seven databases. Critical appraisal of studies was carried out using the Scottish Intercollegiate Guidelines Network (SIGN) checklist. Pooled risk of major injuries was assessed using the random effects meta-analytic model. Heterogeneity was quantified using I-squared and Tau-squared statistics. Funnel plots and Egger's test were used to investigate publication bias. This review is registered in PROSPERO (CRD42015020309).ResultsEleven studies, all carried out in developed countries were included. Overall, the risk of any major injury was significantly lower in belted passengers compared to unbelted passengers (RR 0.47; 95%CI, 0.29 to 0.80; I-2=99.7; P=0.000). When analysed by crash types, belt use significantly reduced the risk of any injury (RR 0.35; 95%CI, 0.24 to 0.52). Seatbelt use reduces the risk of facial injuries (RR=0.56, 95% CI=0.37 to 0.84), abdominal injuries (RR=0.87; 95% CI=0.78 to 0.98) and, spinal injuries (RR=0.56, 95% CI=0.37 to 0.84). However, we found no statistically significant difference in risk of head injuries (RR=0.49; 95% CI=0.22 to 1.08), neck injuries (RR=0.69: 95%CI 0.07 to 6.44), thoracic injuries (RR 0.96, 95%CI, 0.74 to 1.24), upper limb injuries (RR=1.05, 95%CI 0.83 to 1.34) and lower limb injuries (RR=0.77, 95%CI 0.58 to 1.04) between belted and non-belted passengers.ConclusionIn sum, the risk of most major road traffic injuries is lower in seatbelt users. Findings were inconclusive regarding seatbelt use and susceptibility to thoracic, head and neck injuries during road traffic accidents. Awareness should be raised about the dangers of inadequate seatbelt use. Future research should aim to assess the effects of seatbelt use on major injuries by crash type

The Effect of Human Immunodeficiency Virus Type-1 Coreceptor Preference on Entry and Tropism Specific Phenotypes

During HIV type 1 (HIV-1) entry, trimers of viral gp120 proteins attach to CD4 molecules and to CCR5 or CXCR4 coreceptors on the target cell. A virus is defined as R5 tropic if it uses CCR5 coreceptors and X4 tropic if it uses CXCR4. In addition to the difference in coreceptor usage, R5 and X4 tropic viruses display other phenotypic differences. R5 virus dominates in early infection even when recipients are co-infected with both viral tropisms. As the disease progresses, the virus evolves and a tropism switch from R5 to X4 occurs in approximately 50% of patients. This study aims to more fully elucidate the mechanisms underlying the phenotypic differences between X4 and R5 virus. The stoichiometric parameters associated with HIV-1 target cell entry remain unclear and may differ depending on coreceptor usage. Important unanswered questions include: how many viral envelope trimers (or spikes) must attach to CD4 molecules, how many must bind coreceptors, and how many functional gp120 subunits per envelope trimer are required for entry? To answer these questions we performed single round infectivity assays with chimeric viruses. Theoretical relative infectivity curves were generated using mathematical models and compared to the experimental curves. Using this methodology we determined that HIV-1 entry requires only a small number (one or two) of functional envelope spikes. Our data indicate that an individual virion has between one and three envelope spikes on its surface that are both functional and able to simultaneously contact a target cell. In addition, our analysis shows that trimeric envelope spikes may function with fewer than three active gp120 subunits. However, our analysis of the entry mechanism indicates that there is no major difference in the stoichiometric requirements for CCR5 versus CXCR4-mediated HIV-1 entry into host cells. To investigate whether factors outside of viral entry machinery differentially affect the fitness of R5 and X4 tropic viruses, we used in vitro techniques to assay infection rates, target cell availability, viral burst size, and the potential negative pressure of the cytotoxic lymphocyte (CTL) response. Our study indicates that R5 virus has a kinetic advantage over X4 virus replication. Our results show that neither CTL suppression nor burst size correlates to tropism and thus is unlikely to play a role in early R5 viral dominance. Contrary to what is seen in newly infected patients, we saw consistently higher rates of infection with X4 virus. Viral growth modeling indicates that target cell availability in our in vitro system is responsible for this apparent X4 replication advantage. Infection rate constants for X4 and R5 virus, which are influenced by infection rate, burst size, and target cell availability, indicate that R5 virus has a more than two fold replication advantage over some of the X4 viral isolates. If target cell availability during early infection does not overwhelmingly favor X4 growth, then this kinetic difference could explain R5’s initial dominance. Overall, our data supports the hypothesis that credits replication rate and target cell availability for dominance of R5 tropic virus and for tropism switching respectively. We conclude that R5 virus more efficiently causes productive infection in its target cells and this gives it a replication advantage until those target cells are depleted. We conclusively show that initial advantage of R5 virus does not come from the entry machinery, from the viral burst size, or from CTL suppression of X4 infected cells

Bilateral National Metrology Institute Comparison of Guarded-Hot-Plate Apparatus

Two national metrology institutes have conducted an international interlaboratory comparison on thermal conductivity for two thermal insulation reference materials. The Laboratoire national de métrologie et d’essais (LNE), France, and the National Institute of Standards and Technology (NIST), United States, present measurements obtained by the guarded-hot-plate method. The study involved two materials: expanded polystyrene board (EPS) and fibrous glass board (FGB). The EPS was provided by the LNE and is issued as a transfer specimen; the FGB provided by NIST was issued as Standard Reference Material (SRM) 1450c. For each reference material, the study was based on four independent measurements at a mean temperature of 24°C and two additional mean temperatures of 10°C and 35°C

Justice Edward Godfrey and the Role of the Trial Judge in the Criminal Process

At the end of 1994 Dean Edward S. Godfrey III stepped down from his teaching position as Professor Emeritus of the University of Maine School of Law. In honor of his service to Maine’s only law school, to the Maine Supreme Judicial Court, to the Maine Bar, and to the people of the State of Maine, the Board and Staff dedicate Volume 47 of the Maine Law Review to Dean Edward Godfrey. Reviews by Maine Law School faculty members of Dean Godfrey’s Law Court decisions in several areas of the law follow