The Correlation between Students\u27 Grades in High School and College Physics

This study was undertaken in order to find out to what extent the achievement of a student in college Physics was similar to his achievement in high school Physics. The high school grades for the entire course of Physics were used in comparison to the first semester grades in college Physics. The data covers the records of students who entered college during a period of three years. The total number of students considered was one hundred twenty-one. With this group the formula proposed by Karl Pearson showed the coefficient of correlation to be 0.62. This is considered quite a marked correlation

Lorentz transmission electron microscopy and magnetic force microscopy characterization of NiFe/Al-oxide/Co films

Magnetization reversal process of NiFe/Al-oxide/Co junction films was observed directly using Lorentztransmission electron microscopy (LTEM) and magnetic force microscopy(MFM).In situmagnetizing experiments performed in both LTEM and MFM were facilitated by a pair of electromagnets, which were mounted on the sample stages. A two-stage magnetization reversal process for the junction film was clearly observed in LTEM with NiFe magnetization reversed first via domain wall motion followed by Co magnetization reversal via moment rotation and domain wall motion. Reversal mechanism and domain characteristics of the NiFe and Co layers showed very distinctive features. The magnetization curve of the junction filmmeasured using alternating gradient force magnetometry showed a nonzero slope at the antiparallel magnetization configuration region, which implies that magnetization directions of the NiFe and Co layers were not exactly antiparallel due to Co moment rotation existed in that region. After the magnetization reversal of the Co was complete, MFM images revealed some magnetic contrast, which suggests that an out-of-plane magnetization component remained in the Co layer. Such magnetic contrast disappeared at higher magnetic fields when the Co moments further rotated and aligned parallel to the applied field direction

Enhancement of superconducting transition temperature by the additional second neighbor hopping t' in the t-J model

Within the kinetic energy driven superconducting mechanism, the effect of the additional second neighbor hopping t' on the superconducting state of the t-J model is discussed. It is shown that t' plays an important role in enhancing the superconducting transition temperature of the t-J model. It is also shown that the superconducting-state of cuprate superconductors is the conventional Bardeen-Cooper-Schrieffer like, so that the basic Bardeen-Cooper-Schrieffer formalism is still valid in quantitatively reproducing the doping dependence of the superconducting gap parameter and superconducting transition temperature, and electron spectral function at $(\pi,0)$ point, although the pairing mechanism is driven by the kinetic energy by exchanging dressed spin excitations.Comment: 8 pages, 4 figures, added discussions and references, accepted for publication in Physics Letters

Modeling afterslip and aftershocks following the 1992 Landers earthquake

One way to probe the rheology of the lithosphere and fault zones is to analyze the temporal evolution of deformation following a large earthquake. In such a case, the lithosphere responds to a known stress change that can be assessed from earthquake slip models constrained from seismology and geodesy. Here, we model the postseismic response of a fault zone that is assumed to obey a rate-strengthening rheology, where the frictional stress varies as aσ ln(ε), ε being the deformation rate and aσ > 0 a rheological parameter. The model is simple enough that these parameters can be estimated by inversion of postseismic geodetic data. We apply this approach to the analysis of geodetic displacements following the M_w 7.3, 1992, Landers earthquake. The model adjusts well the measured displacements and implies aσ ≈ 0.47–0.53 MPa. In addition, we show that aftershocks and afterslip follow the same temporal evolution and that the spatiotemporal distribution of aftershocks is consistent with the idea that they are driven by reloading of the seismogenic zone resulting from frictional afterslip

Earthquakes: from chemical alteration to mechanical rupture

In the standard rebound theory of earthquakes, elastic deformation energy is progressively stored in the crust until a threshold is reached at which it is suddenly released in an earthquake. We review three important paradoxes, the strain paradox, the stress paradox and the heat flow paradox, that are difficult to account for in this picture, either individually or when taken together. Resolutions of these paradoxes usually call for additional assumptions on the nature of the rupture process (such as novel modes of deformations and ruptures) prior to and/or during an earthquake, on the nature of the fault and on the effect of trapped fluids within the crust at seismogenic depths. We review the evidence for the essential importance of water and its interaction with the modes of deformations. Water is usually seen to have mainly the mechanical effect of decreasing the normal lithostatic stress in the fault core on one hand and to weaken rock materials via hydrolytic weakening and stress corrosion on the other hand. We also review the evidences that water plays a major role in the alteration of minerals subjected to finite strains into other structures in out-of-equilibrium conditions. This suggests novel exciting routes to understand what is an earthquake, that requires to develop a truly multidisciplinary approach involving mineral chemistry, geology, rupture mechanics and statistical physics.Comment: 44 pages, 1 figures, submitted to Physics Report

COAST (Cisplatin ototoxicity attenuated by aspirin trial): A phase II double-blind, randomised controlled trial to establish if aspirin reduces cisplatin induced hearing-loss

Background: Cisplatin is one of the most ototoxic chemotherapy drugs, resulting in a permanent and irreversible hearing loss in up to 50% of patients. Cisplatin and gentamicin are thought to damage hearing through a common mechanism, involving reactive oxygen species in the inner ear. Aspirin has been shown to minimise gentamicin-induced ototoxicity. We, therefore, tested the hypothesis that aspirin could also reduce ototoxicity from cisplatin-based chemotherapy. Methods: A total of 94 patients receiving cisplatin-based chemotherapy for multiple cancer types were recruited into a phase II, double-blind, placebo-controlled trial and randomised in a ratio of 1:1 to receive aspirin 975 mg tid and omeprazole 20 mg od, or matched placebos from the day before, to 2 days after, their cisplatin dose(s), for each treatment cycle. Patients underwent pure tone audiometry before and at 7 and 90 days after their final cisplatin dose. The primary end-point was combined hearing loss (cHL), the summed hearing loss at 6 kHz and 8 kHz, in both ears. Results: Although aspirin was well tolerated, it did not protect hearing in patients receiving cisplatin (p-value = 0.233, 20% one-sided level of significance). In the aspirin arm, patients demonstrated mean cHL of 49 dB (standard deviation [SD] 61.41) following cisplatin compared with placebo patients who demonstrated mean cHL of 36 dB (SD 50.85). Women had greater average hearing loss than men, and patients treated for head and neck malignancy experienced the greatest cHL. Conclusions: Aspirin did not protect from cisplatin-related ototoxicity. Cisplatin and gentamicin may therefore have distinct ototoxic mechanisms, or cisplatin-induced ototoxicity may be refractory to the aspirin regimen used here

The 1928 eruption of Mount Etna (Italy): Reconstructing lava flow evolution and the destruction and recovery of the town of Mascali

Abstract Mount Etna in Sicily (Italy) shows more than 2,500 years of interactions between volcanic eruptions and human activity, and these are well documented in historical sources. During the last 400 years, flank eruptions have had major impacts on the urban fabric of the Etna region, especially in 1651, 1669, 1923 and 1928, and it is the last of these which is the focus of this paper. In this paper a detailed field and historical reconstruction of the 1928 eruption is presented which allows three themes to be discussed: the evolution of the flow field, lava volume and average magma discharge rate trend; the eruption's human impact, particularly the destruction of the town of Mascali; and the recovery of the region with re-construction of Mascali in a new location. Detailed mapping of lava flows allowed the following dimensions to be calculated: total area, 4.38 x 106 m2; maximum length, 9.4 km; volume, 52.91 ± 5.21 × 106m3 and an average effusion rate of 38.5 m3 s-1. Time-averaged discharged rates are calculated allowing the reconstruction of their temporal variations during the course of the eruption evidencing a high maximum effusion rate of 374 m3 s-1. These trends, in particular with regard to the Lower Fissure main phase of the eruption, are in accordance with the ‘idealized discharge model’ of Wadge (1981), proposed for basaltic eruptions driven by de-pressurization of magma sources, mainly through reservoir relaxation (i.e. elastic contraction of a magma body). The eruption took place when Italy was governed by Mussolini and the fascist party. The State response both, during and in the immediate aftermath of the eruption and in the years that followed during which Mascali was reconstructed, was impressive. This masked a less benign legacy, however, that can be traced for several subsequent decades of using responses to natural catastrophes to manufacture State prestige by reacting to, rather than planning for, disasters

Relation between Corticosterone and Fear-related Behavior in Mice Selectively Bred for High or Low Alcohol Preference

Blunted cortisol responses to stress or trauma have been linked with genetic (familial) risk for both alcoholism and post-traumatic stress-disorder (PTSD). Mouse lines selectively bred for high (HAP) or low (LAP) alcohol preference may be a relevant model of genetic risk for co-morbid alcoholism and PTSD in humans. HAP mice show greater fear-potentiated startle (FPS), a model used to study PTSD, than LAP mice. The relation between corticosterone (CORT) and FPS behavior was explored in four experiments. Naïve male and female HAP2 and LAP2 mice received fear-conditioning or control treatments and CORT levels were measured before and immediately after fear-conditioning or FPS testing. In two other experiments, HAP2 mice received CORT (1.0, 5.0, or 10.0 mg/kg) or a glucocorticoid receptor antagonist (mifepristone; 25.0 and 50.0 mg/kg) 30 min before fear-conditioning. HAP2 mice exposed to fear-conditioning and to control foot shock exposures showed lower CORT after the fear-conditioning and FPS testing sessions than LAP2 mice. A trend toward higher FPS was seen in HAP2 mice pretreated with 10.0 mg/kg CORT and CORT levels were the lowest in this group, suggesting negative feedback inhibition of CORT release. Mifepristone did not alter FPS. Overall, these results are consistent with data in humans and rodents indicating that lower cortisol/CORT levels after stress are associated with PTSD/PTSD-like behavior. These findings in HAP2 and LAP2 mice suggest that a blunted CORT response to stress may be a biological marker for greater susceptibility to develop PTSD in individuals with increased genetic risk for alcoholism