Eighth Grade Students' Understandings of Groundwater

According to national standards, eighth graders should possess appropriate understandings regarding groundwater and its role in the hydrologic cycle. This article describes a study of eighth-grade students to determine what types of ideas eighth graders actually possess regarding groundwater. The students completed a survey that consisted of one multiple-choice item and a drawing prompt. The results of this survey, along with videotaped class discussions about goundwater, revealed that students of this age group hold naive conceptions concerning groundwater. In addition, the students' spatial reasoning was identified as contributing to their conceptions. Educational levels: Graduate or professional, Graduate or professional

Initial Conditions, Institutional Dynamics and Economic Performance: Evidence from the American States

Using state-level data from the United States, we find that differences in colonial legal institutions affect the current quality of state legal institutions. These differences in colonial legal institutions arose because some states were settled by Great Britain, a common law country, and other states were settled by France, Spain, and Mexico, all civil law countries. To explain these findings, we develop a transplant-civil law hypothesis that highlights the disruption associated with large-scale legal transplantation and the possible relative inefficiencies of colonial civil law. We find strong support for the transplant-civil law hypothesis. Our results are robust to inclusion of additional variables capturing climate, geography, initial population and resource endowments. Given the 150-200 year gap between the initial conditions and the measures of the current quality of legal institutions, we provide indirect evidence on the persistence of legal institutions. We then use initial legal systems and climate to quantify the substantial impact of current institutions on current economic performance.http://deepblue.lib.umich.edu/bitstream/2027.42/40001/3/wp615.pd

Legal Origins and the Evolution of Institutions: Evidence from American State Courts

Several important studies of institutions assume that the quality of institutions is persistent following some formative historic event. The assumption of institutional persistence, however, begs the question of how these institutions persisted. To better understand this issue, this paper examines the evolution of state courts in the United States. We begin by reviewing the evidence that France, Spain, and Mexico operated civil-law legal systems in territory that would later make up thirteen states. One important philosophical difference between civil-law and common-law legal systems arises from differences in their beliefs regarding the appropriate degree of judicial independence. To show how these beliefs, if persistent, would manifest themselves, we present a model in which legislatures allocate budgets to their judges. In the model, common and civil-law legislatures have different preferences regarding the level of judicial independence. Our model predicts civil-law legislatures will give fewer discretionary resources to their judges when judicial elections are replaced by a system of appointments. We confirm this prediction using state-level data for the period 1961-1999. Finally, we argue that one important reason why civil-law preferences for a weak judiciary appear to have persisted in the American states is that the political culture within state legislatures is slow-moving.

Activity of species-specific antibiotics against Crohnʼs disease–associated adherent-invasive Escherichia coli

Background: Crohn's disease (CD) is associated with bacterial dysbiosis that frequently includes colonization by adherent-invasive Escherichia coli (AIEC). AIEC are adept at forming biofilms and are able to invade host cells and stimulate the production of proinflammatory cytokines. The use of traditional antibiotics for the treatment of CD shows limited efficacy. In this study, we investigate the use of species-specific antibiotics termed colicins for treatment of CD-associated AIEC. Methods: Colicin activity was tested against a range of AIEC isolates growing in the planktonic and biofilm mode of growth. Colicins were also tested against AIEC bacteria associated with T84 intestinal epithelial cells and surviving inside RAW264.7 macrophages using adhesion assays and gentamicin protection assay, respectively. Uptake of colicins into eukaryotic cells was visualized using confocal microscopy. The effect of colicin treatment on the production of proinflammatory cytokine tumor necrosis factor alpha by macrophages was assessed by an enzyme-linked immunosorbent assay. Results: Colicins show potent activity against AIEC bacteria growing as biofilms when delivered either as a purified protein or through a colicin-producing bacterial strain. In addition, colicins E1 and E9 are able to kill cell-associated and intracellular AIEC, but do not show toxicity toward macrophage cells or stimulate the production of proinflammatory cytokines. Colicin killing of intracellular bacteria occurs after entry of colicin protein into AIEC-infected macrophage compartments by actin-mediated endocytosis. Conclusions: Our results demonstrate the potential of colicins as highly selective probiotic therapeutics for the eradication of E. coli from the gastrointestinal tract of patients with CD

Initial Conditions, Institutional Dynamics and Economic Performance: Evidence from the American States

Using state-level data from the United States, we find that differences in colonial legal institutions affect the current quality of state legal institutions. These differences in colonial legal institutions arose because some states were settled by Great Britain, a common law country, and other states were settled by France, Spain, and Mexico, all civil law countries. To explain these findings, we develop a transplant-civil law hypothesis that highlights the disruption associated with large-scale legal transplantation and the possible relative inefficiencies of colonial civil law. We find strong support for the transplant-civil law hypothesis. Our results are robust to inclusion of additional variables capturing climate, geography, initial population and resource endowments. Given the 150-200 year gap between the initial conditions and the measures of the current quality of legal institutions, we provide indirect evidence on the persistence of legal institutions. We then use initial legal systems and climate to quantify the substantial impact of current institutions on current economic performance.common law, civil law, transplant, initial conditions, state courts and public corruption

Orthostatic-induced Hypotension Attenuates Cold Pressor Pain Perception

In recent years, numerous studies have established a connection between blood pressure and nocioception. While this connection is well documented in the literature, its underlying physiological mechanisms have yet to be elucidated. Much attention has focused on the relationship between cardiovascular regulatory centers and nocioception, yet the intricacies of this relationship have not been fully explored. Therefore, the purpose of this investigation was to examine the role of the baroreflex system as a modulator of pain perception. Twenty normotensive males participated in two laboratory sessions. Time to cold pain threshold and pain tolerance was measured at rest during the first visit. On visit two, blood pressure was orthostatically manipulated via tilt table at postures 90o, 120o, and 180o. Orthostatic manipulation significantly lowered systolic blood pressure (SBP), pain threshold, and pain tolerance from seated baseline at 120o and 180o. The regression models for baroreceptor reflex sensitivity (BRS) assessed during seated baseline and at 120o and 180o revealed a significant negative beta weight for the effect of SBP. A significant negative beta weight for the effects of BRS, SBP, and their interaction was observed at 90o. In conclusion, orthostatic baroreceptor activation appears to exert an inhibitory effect on the brain that decreases pain sensitivity

Unmasking Pain: A Look at the Latest Research

Recent research into the physical and psychological mechanisms of pain in revealing new ways to help ease the hurt without the use of medication

Exercise Intensity as a Determinant of Exercise Induced Hypoalgesia

The purpose of this study was to examine pain perception during and following two separate 30-min bouts of exercise above and below the Lactate Threshold (LT). Pain Threshold (PT) and Pain Intensity (PI) were monitored during (15 and 30 min) and after exercise (15 and 30 min into recovery) using a Cold Pressor Test (CPT) and Visual Analog Scale (VAS) for pain of the non-dominant hand. Significant differences in PT scores were found both during and after exercise conditions. Post hoc analysis revealed significant differences in PT scores at 30 min of exercise (P=0.024, P=0.02) and 15 min of recovery (P=0.03, P=0.01) for exercise conditions above and below LT, respectively. No differences (P=0.05) in PT scores were found at any time point between exercise conditions. No differences were found in PI scores at any time point within each trial (P=0.05) as well as between exercise conditions (p=0.05). Based upon these data, the effects of moderate exercise on PT appear to be similar at exercise intensities just above and below LT. This may indicate that the requisite intensity needed to ellicit Exercise-Induced Hypoalgesia may be lower than previously reported. Because a hypoalgesic effect was not observed in either condition until 30 min of exercise had been completed, total exercise time may be an important factor in the augmentation of pain perception under these conditions