Which School Attributes Matter? The Influence of School District Performance and Demographic Composition on Property Values

Increasing levels of segregation in American schools raises the question: do home buyers pay for test scores or demographic composition? This paper uses Connecticut panel data spanning eleven years from 1994 to 2004 to ascertain the relationship between property values and explanatory variables that include school district performance and demographic attributes, such as racial and ethnic composition of the student body. Town and census tract fixed effects are included to control for neighborhood unobservables. The effect of changes in school district attributes is also examined over a decade long time frame in order to focus on the effect of long run changes, which are more likely to be capitalized into prices. The study finds strong evidence that increases in percent Hispanic has a negative effect on housing prices in Connecticut, but mixed evidence concerning the impact of test scores on property values. Evidence is also found to suggest that student test scores have increased in importance for explaining housing prices in recent years while the importance of percent Hispanic has declined. Finally, the study finds that estimates of property tax capitalization increase substantially when the analysis focuses on long run changes.

Signal relay between two integral membrane proteins: The sensory rhodopsin I/HtrI transducer molecular complex

The molecular complex of sensory rhodopsin I (SRI) and its transducer HtrI mediate color-sensitive phototaxis in the archaeon Halobacterium salinarum. Orange light causes an attractant response by a one-photon reaction and white light causes a repellent response by a two-photon reaction. Three aspects of this molecular complex were explored: (i) We determined the stoichiometry of SRI and HtrI to be 2:2 by gene fusion analysis. A SRI-HtrI fusion protein was expressed in H. salinarum and shown to mediate 1-photon and 2-photon phototaxis responses comparable to wild-type complex. Disulfide crosslinking demonstrated that the fusion protein is a homodimer in the membrane. Measurement of photochemical reaction kinetics and pH titration of absorption spectra established that both SRI domains are complexed to HtrI in the fusion protein, and therefore the stoichiometry is 2:2. (ii) Cytoplasmic channel closure of SRI by HtrI, an important aspect of their interaction, was investigated by incremental HtrI truncation. We found that binding of the membrane-embedded portion of HtrI is insufficient for channel closure, whereas cytoplasmic extension of the second HtrI transmembrane helix by 13 residues blocks proton conduction through the channel as well as full-length HtrI. The closure activity is localized to 5 specific residues, each of which incrementally contributes to reduction of proton conductivity. Moreover, these same residues in the dark incrementally and proportionally increase the pKa of the Asp76 counterion to the protonated Schiff base chromophore. We conclude that this critical region of HtrI alters the dark conformation of SRI as well as light-induced channel opening. (iii) We developed a procedure for reconstituting HtrI-free SRI and the SRI/HtrI complex into liposomes, which exhibit photocycles with opened and closed cytoplasmic channels, respectively, as in the membrane. This opens the way for study of the light-induced conformational change and the interaction in vitro by fluorescence and spin-labeling. Single-cysteine mutations were introduced into helix F of SRI, labeled with a nitroxide spin probe and a fluorescence probe, reconstituted into proteoliposomes, and light-induced conformational changes detected in the complex. The probe signals can now be used as the readout of signaling to analyze mutants and the kinetics of signal relay. ^

Long-term hyperexcitability of sensory and motor axons in Aplysia californica: Induction by axotomy, serotonin, and transient depolarization

Neuropathic pain is a debilitating neurological disorder that may appear after peripheral nerve trauma and is characterized by persistent, intractable pain. The well-studied phenomenon of long-term hyperexcitability (LTH), in which sensory somata become hyperexcitable following peripheral nerve injury may be important for both chronic pain and long-lasting memory formation, since similar cellular alterations take place after both injury and learning. Though axons have previously been considered simple conducting cables, spontaneous afferent signals develop from some neuromas that form at severed nerve tips, indicating intrinsic changes in sensory axonal excitability may contribute to this intractable pain. Here we show that nerve transection, exposure to serotonin, and transient depolarization induce long-lasting sensory axonal hyperexcitability that is localized to the treated nerve segment and requires local translation of new proteins. Long-lasting functional plasticity may be a general property of axons, since both injured and transiently depolarized motor axons display LTH as well. Axonal hyperexcitability may represent an adaptive mechanism to overcome conduction failure after peripheral injury, but also displays key features shared with cellular analogues of memory including: site-specific changes in neuronal function, dependence on transient, focal depolarization for induction, and requirement for synthesis of new proteins for expression of long-lasting effects. The finding of axonal hyperexcitability after nerve injury sheds new light on the clinical problem of chronic neuropathic pain, and provides more support for the hypothesis that mechanisms of long-term memory storage evolved from primitive adaptive responses to injury. ^

Exploring parents' memories of their child's death related sensory experiences as a dimension of grieving

Little is known about how dying children and their parents experience death. Dying children have reported death related sensory experiences (DRSEs), defined as seeing or hearing someone or something not visible or audible to others, associated with dying. Although parents report that they and the dying child benefit from these experiences, healthcare providers often unknowingly dismiss them. The aims of this phenomenological inquiry were to describe children's DRSEs and their meaning from the parents' perspectives. Four fathers and six mothers of African American, Caucasian, or Hispanic ethnicity, all Christian, ranging in age from 35 to 59 years, whose child died 23 to 52 months prior and was treated at a children's cancer center, were interviewed in the home or hospital setting of their choice. Children's ages at the time of their death ranged from 4 to 13 years. A modification of van Kaarn's phenomenological method of analysis was used to analyze data. Themes emerging from the data for the first aim were: perceiving someone or something from a spiritual realm others could not, expressing awareness tempered by parental reactions, and embracing transcendence. Themes emerging from the data for the second aim were: spiritual beings prepared child; child revealed reality, preparing parents; and child transcended wholly, easing parents' grief. Post-interview surveys revealed that parents found participating in this study a "very positive" or "positive" experience, particularly being able to tell the story of their child. Children's DRSEs have clinical implications for all who provide care near the end of life. Informing parents of DRSEs, cautioning that not all dying children express them, may help parents to anticipate this phenomenon, which may decrease anxiety when their child expresses them, increasing the opportunity for open dialogue between parent and child about dying and death, and decrease regrets associated with being unreceptive to their child's expressions of death awareness. Validating a child's DRSE can have profound effects on bereaved parents. Examining DRSEs from the child's perspective and the influence of informing parents of DRSEs on the dying experience of the child and the parental grieving process are recommended. ^

Molecular interactions and signal transfer between sensory rhodopsin-I and its cognate transducer

SRI is unique among known photoreceptors in that it produces opposite signals depending on the color of light stimuli. Absorption of orange light (587 nm) triggers an attractant response by the cell, whereas absorption of orange light followed by near-UV light (373 run) triggers a repellent response. Using behavioral mutants that exhibit aberrant color-sensing ability, we tested a two-conformation equilibrium model, using FRET and EPR spectroscopy. The essence of the model applied to SRI-HtrI is that the complex exists in a metastable two-conformer equilibrium which is shifted in one direction by orange light absorption (producing an attractant signal) and in the opposite direction by a second UV-violet photon (producing a repellent signal). First, by FRET we found that the E-F cytoplasmic loop of SRI moves toward the RAMP domain of the HtrI transducer during the formation of the orange-light activated signaling state of the complex. This is the first localization of a change in the physical relationship between the receptor and transducer subunits of the complex and provides a structural property of the two proposed conformers that we can monitor. Second, EPR spectra of a spin label probe at this cytoplasmic position showed shifts in the dark in the mutants toward shorter or longer EF loop-RAMP distances, explaining their behavior in terms of their mutations causing pre-stimulus shifts into one or the other conformer. ^ Next, we applied a novel electrophysiological method for monitoring the directionality of proton movement during photoactivation of SRI, to investigate the process of proton transfer in the photoactive site from the chromophore to proton acceptors on both the wildtype and aberrant color-response mutants. We observed an unexpected and critical difference in the two signaling conformations of the SRI-HtrI complex. The finding is that the vectoriality (i.e. movement away or toward the cytoplasm) of the light-induced proton transfer from the chromophore to the protein is opposite in formation of the two conformations. Retinylidene proton transfer is a common critical process in rhodopsins and these results are the first to show differences in vectoriality in a rhodopsin receptor, and to demonstrate functional importance of the direction of proton transfer. ^

UNDERSTANDING INTERRUPTIONS IN HEALTHCARE: DEVELOPING A MODEL

Developing a Model Interruption is a known human factor that contributes to errors and catastrophic events in healthcare as well as other high-risk industries. The landmark Institute of Medicine (IOM) report, To Err is Human, brought attention to the significance of preventable errors in medicine and suggested that interruptions could be a contributing factor. Previous studies of interruptions in healthcare did not offer a conceptual model by which to study interruptions. As a result of the serious consequences of interruptions investigated in other high-risk industries, there is a need to develop a model to describe, understand, explain, and predict interruptions and their consequences in healthcare. Therefore, the purpose of this study was to develop a model grounded in the literature and to use the model to describe and explain interruptions in healthcare. Specifically, this model would be used to describe and explain interruptions occurring in a Level One Trauma Center. A trauma center was chosen because this environment is characterized as intense, unpredictable, and interrupt-driven. The first step in developing the model began with a review of the literature which revealed that the concept interruption did not have a consistent definition in either the healthcare or non-healthcare literature. Walker and Avant’s method of concept analysis was used to clarify and define the concept. The analysis led to the identification of five defining attributes which include (1) a human experience, (2) an intrusion of a secondary, unplanned, and unexpected task, (3) discontinuity, (4) externally or internally initiated, and (5) situated within a context. However, before an interruption could commence, five conditions known as antecedents must occur. For an interruption to take place (1) an intent to interrupt is formed by the initiator, (2) a physical signal must pass a threshold test of detection by the recipient, (3) the sensory system of the recipient is stimulated to respond to the initiator, (4) an interruption task is presented to recipient, and (5) the interruption task is either accepted or rejected by v the recipient. An interruption was determined to be quantifiable by (1) the frequency of occurrence of an interruption, (2) the number of times the primary task has been suspended to perform an interrupting task, (3) the length of time the primary task has been suspended, and (4) the frequency of returning to the primary task or not returning to the primary task. As a result of the concept analysis, a definition of an interruption was derived from the literature. An interruption is defined as a break in the performance of a human activity initiated internal or external to the recipient and occurring within the context of a setting or location. This break results in the suspension of the initial task by initiating the performance of an unplanned task with the assumption that the initial task will be resumed. The definition is inclusive of all the defining attributes of an interruption. This is a standard definition that can be used by the healthcare industry. From the definition, a visual model of an interruption was developed. The model was used to describe and explain the interruptions recorded for an instrumental case study of physicians and registered nurses (RNs) working in a Level One Trauma Center. Five physicians were observed for a total of 29 hours, 31 minutes. Eight registered nurses were observed for a total of 40 hours 9 minutes. Observations were made on either the 0700–1500 or the 1500-2300 shift using the shadowing technique. Observations were recorded in the field note format. The field notes were analyzed by a hybrid method of categorizing activities and interruptions. The method was developed by using both a deductive a priori classification framework and by the inductive process utilizing line-byline coding and constant comparison as stated in Grounded Theory. The following categories were identified as relative to this study: Intended Recipient - the person to be interrupted Unintended Recipient - not the intended recipient of an interruption; i.e., receiving a phone call that was incorrectly dialed Indirect Recipient – the incidental recipient of an interruption; i.e., talking with another, thereby suspending the original activity Recipient Blocked – the intended recipient does not accept the interruption Recipient Delayed – the intended recipient postpones an interruption Self-interruption – a person, independent of another person, suspends one activity to perform another; i.e., while walking, stops abruptly and talks to another person Distraction – briefly disengaging from a task Organizational Design – the physical layout of the workspace that causes a disruption in workflow Artifacts Not Available – supplies and equipment that are not available in the workspace causing a disruption in workflow Initiator – a person who initiates an interruption Interruption by Organizational Design and Artifacts Not Available were identified as two new categories of interruption. These categories had not previously been cited in the literature. Analysis of the observations indicated that physicians were found to perform slightly fewer activities per hour when compared to RNs. This variance may be attributed to differing roles and responsibilities. Physicians were found to have more activities interrupted when compared to RNs. However, RNs experienced more interruptions per hour. Other people were determined to be the most commonly used medium through which to deliver an interruption. Additional mediums used to deliver an interruption vii included the telephone, pager, and one’s self. Both physicians and RNs were observed to resume an original interrupted activity more often than not. In most interruptions, both physicians and RNs performed only one or two interrupting activities before returning to the original interrupted activity. In conclusion the model was found to explain all interruptions observed during the study. However, the model will require an even more comprehensive study in order to establish its predictive value.

The role of the intracellular second messenger cAMP in the induction of long-term morphological changes in sensory neurons of {\it Aplysia\/}

The present work examines the role of cAMP in the induction of the type of long-term morphological changes that have been shown to be correlated with long-term sensitization in Aplysia.^ To examine this issue, cAMP was injected into individual tail sensory neurons in the pleural ganglion to mimic, at the single cell level, the effects of behavioral training. After a 22 hr incubation period, the same cells were filled with horseradish peroxidase and 2 hours later the tissue was fixed and processed. Morphological analysis revealed that cAMP induced an increase in two morphological features of the neurons, varicosities and branch points. These structural alterations, which are similar to those seen in siphon sensory neurons of the abdominal ganglion following long-term sensitization training of the siphon-gill withdrawal reflex, could subserve the altered behavioral response of the animal. These results expose another role played by cAMP in the induction of learning, the initiation of a structural substrate, which, in concert with other correlates, underlies learning.^ cAMP was injected into sensory neurons in the presence of the reversible protein synthesis inhibitor, anisomycin. The presence of anisomycin during and immediately following the nucleotide injection completely blocked the structural remodeling. These results indicate that the induction of morphological changes by cAMP is a process dependent on protein synthesis.^ To further examine the temporal requirement for protein synthesis in the induction of these changes, the time of anisomycin exposure was varied. The results indicate that the cellular processes triggered by cAMP are sensitive to the inhibition of protein synthesis for at least 7 hours after the nucleotide injection. This is a longer period of sensitivity than that for the induction of another correlate of long-term sensitization, facilitation of the sensory to motor neuron synaptic connection. Thus, these findings demonstrate that the period of sensitivity to protein synthesis inhibition is not identical for all correlates of learning. In addition, since the induction of the morphological changes can be blocked by anisomycin pulses administered at different times during and following the cAMP injection, this suggests that cAMP is triggering a cascade of protein synthesis, with successive rounds of synthesis being dependent on successful completion of preceding rounds. Inhibition at any time during this cascade can block the entire process and so prevent the development of the structural changes.^ The extent to which cAMP can mimic the structural remodeling induced by long-term training was also examined. Animals were subjected to unilateral sensitization training and the morphology of the sensory neurons was examined twenty-four hours later. Both cAMP injection and long-term training produced a twofold increase in varicosities and approximately a fifty percent increase in the number of branch points in the sensory neuron arborization within the pleural ganglion. (Abstract shortened by UMI.) ^

The cGMP -PKG pathway is critical for inducing long-term sensitization of identified nociceptive sensory neurons

In various species, peripheral injury produces long-lasting sensitization of central and peripheral neurons representing the affected area. In Aplysia, memory-like traces (lasting days or weeks) of noxious peripheral stimulation include enhancement of central synaptic transmission and enhanced excitability of the central soma and peripheral branches of nociceptive sensory neurons. An important role for the cAMP-PKA-CREB pathway in consolidating long-term memory and inducing transcription-dependent synaptic potentiation has also been indicated by studies in rodents and Drosophila. ^ Much less attention has been paid to the cGMP-PKG pathway for transcription-dependent plasticity. Nevertheless, the cGMP-PKG pathway has been implicated in activity-dependent neural alterations lasting hours, and may trigger some forms of persistent pain. Recent evidence indicates PKG can regulate gene expression in the brain and several properties make it an attractive candidate for inducing long-term memories. ^ This dissertation reports that brief, noxious stimulation of a behaving, semi-intact preparation from mollusc, Aplysia californica, produces transcription-dependent, long-term hyperexcitability (LTH) of nociceptive sensory neurons that requires a nitric oxide (NO)-cGMP-protein kinase G (PKG) pathway and which lasts for at least 24 hours. Intracellular injection of cGMP is sufficient to induce LTH. Similarly, body wall injury induces LTH which can be blocked with specific inhibitors of the NO-cGMP-PKG pathway such as L-NMMA, ODQ, Rp-8-cGMPS, PKI-G and KT5823 by isolated perfusion of pleural ganglion sensory cells in or directly by intracellular injection. In contrast, specific inhibitors of the cAMP-PKA pathway (Rp-8-cAMPS, PKI-A and H-89) failed to block injury-induced LTH. Interestingly, co-injection of the cAMP-responsive element (CRE) blocked the induction of both cAMP and injury-induced LTH, but not cGMP-induced LTH. Furthermore, co-injection of cAMP and cGMP with the Ca2+ buffer BAPTA in reduced Ca2+ seawater blocked cAMP-, but not cGMP-induced LTH. These findings demonstrate that the NO-cGMP-PKG pathway and at least one other pathway (perhaps mediated by Ca2+), but not the cAMP-PKA pathway, are critical for inducing LTH during transient, noxious stimulation.^

Influencia del tiempo de maceración sobre el color, la composición tánica y la astringencia de vinos Cabernet Sauvignon y Malbec de Argentina

El objetivo fue determinar qué tiempo de maceración permite una mayor expresión del color y del cuerpo y una menor astringencia en vinos Cabernet Sauvignon (CS) y Malbec (M), de Mendoza, Argentina. A partir de dos vinificaciones industriales de 20 000 L se llevó a cabo un experimento (n = 3) probando tres tiempos de maceración: 5, 10 y 20 días, mediante sucesivos descubes de 60 L. En los vinos resultantes se determinaron fenoles totales, taninos condensados totales, índice de gelatina, intensidad colorante, matiz, color copigmentado y color polimérico, mediante técnicas de espectrofotometría VIS y UV. Los vinos fueron evaluados por un panel de degustadores expertos. Los CS obtenidos con maceración de 10 y 20 días fueron similares y resultaron superiores a los de 5 días en contenidos de antocianos, color polimérico y taninos. También provocaron sensaciones de concentración y untuosidad mayores. Además resultaron más ásperos, astringentes y secantes que los de 5 días, pero estas sensaciones no alcanzaron notas elevadas. Los vinos CS de 20 días alcanzaron contenidos de polifenoles totales y de taninos no precipitables con gelatina mayores que los CS de 10 días. Los vinos M de 10 lograron mayores intensidades colorantes, polifenoles tales, antocianos, color polimérico y taninos que los de 5 y 20 días. Esto se asoció con sensaciones de concentración y untuosidad intensas y similares a las de los CS de 10 y 20 días pero con menos aspereza, astringencia y secante. Los M de 5 días resultaron muy pobres en atributos y los de 20 días con características intermedias entre los M de 5 y los M de 10 días. Tomando en cuenta las dos variedades y los tres tiempos de maceración, cuanto mayor fue el tiempo de maceración menor fue la proporción de antocianos copigmentados y mayor la de antocianos polimerizados. Los polifenoles totales y los taninos se correlacionaron positivamente con la aspereza, la astringencia, lo secante, la untuosidad y la concentración. Lo secante se asoció negativamente con la proporción de taninos no precipitables con gelatina.

Effect of fibers and whole grain content on quality attributes

Incorporation of fiber in cereals may lead to quality issues, thus decreasing consumer acceptance. This is partially due to deterioration of the microstructure, one of the primary quality attributes of cereals. The objective of this study was to better understand the mechanisms by which dietary fibers affect the quality of cereal products during extrusioncooking. The study quantified the effect of amount and type of fiber and whole grain on (i) texture, (ii) structure, and (iii) rehydration properties of extruded cereals. New innovative methods were applied and combined with traditional techniques to characterize both the structure and the rehydration properties. Extruded cereals were produced using a starch-based recipe (whole and wheat flours) and two sources of fibers (oat bran concentrate and wheat bran). The oat and wheat bran levels used in this study were 0, 10, and 20%. The different mixtures were extruded in a pilot twinscrew extruder BC21 (Clextral) and then sugar coated after drying. Mechanical properties of extruded cereals were investigated by compression test. The cellular structure was observed by X-ray tomography. The quality of coating (thickness, homogeneity) was analyzed by optical coherence tomography. The rehydration properties of such cereals in milk were evaluated by magnetic resonance imaging and optical coherence tomography. This work revealed that structure assessment of extruded cereals may lead to a better understanding of the effect of fiber addition on texture and rehydration properties. The application of innovative methods, such as optical coherence tomography and magnetic resonance imaging, was found to be useful to quantify the structural properties.

Using quantitative descriptive analysis and temporal dominance of sensations analysis as complementary methods for profiling commercial blackcurrant squashes

Quantitative descriptive analysis (QDA) is used to describe the nature and the intensity of sensory properties from a single evaluation of a product, whereas temporal dominance of sensation (TDS) is primarily used to identify dominant sensory properties over time. Previous studies with TDS have focused on model systems, but this is the first study to use a sequential approach, i.e. QDA then TDS in measuring sensory properties of a commercial product category, using the same set of trained assessors (n = 11). The main objectives of this study were to: (1) investigate the benefits of using a sequential approach of QDA and TDS and (2) to explore the impact of the sample composition on taste and flavour perceptions in blackcurrant squashes. The present study has proposed an alternative way of determining the choice of attributes for TDS measurement based on data obtained from previous QDA studies, where available. Both methods indicated that the flavour profile was primarily influenced by the level of dilution and complexity of sample composition combined with blackcurrant juice content. In addition, artificial sweeteners were found to modify the quality of sweetness and could also contribute to bitter notes. Using QDA and TDS in tandem was shown to be more beneficial than each just on its own enabling a more complete sensory profile of the products.