115 research outputs found
Effects of New Hampshire\u27s same-sex marriage legislation on married same-sex couples and their families: A preliminary study
This study explores the effects of New Hampshire\u27s revised marriage statute and the ability to marry on married, resident same-sex couples and their families. The researcher used qualitative research methods in order to investigate the experiences of eleven participants in regards to the effects that marriage has had in their lives and the lives of their dependent and adult children. Based on the data and content analysis, a grounded theory of developing a same-sex marital identity emerged showing that the effects of marriage depend on an on-going interplay between personal and social contexts. Participants\u27 lives were affected by marriage in multiple and varied ways based on their spousal relationship, personal surroundings, and interactions with those in their families and communities. Discrepancies between state and national laws governing marriage also influenced the way that marriage impacted the lives of participant couples
Effects of Lesson Sequencing on Preservice Teachers’ Mathematical Knowledge of Place-Value
ABSTRACT
The Effects of Lesson Sequencing on Preservice Teachers' Place-Value Knowledge
Diana Royea
Elementary students' mathematical achievement is a focal point of mathematics education research. Place-value is a foundational topic in the elementary mathematics curriculum. In order to teach place-value in a manner that is in line with mathematics reform practices, teachers must possess strong conceptual, procedural, and specialized content knowledge (SCK) of place-value. At the same time, preservice teachers tend possess mathematical knowledge that is conceptually and procedurally weak. This study used a pretest-posttest design to investigate the effects of lesson sequencing on preservice teachers' conceptual, procedural, SCK, and transfer knowledge of place-value. Preservice teachers were assigned to one of three conditions: Concepts-first, Procedures-First, or Iterative. All of the participants were exposed to the same eight lessons, four conceptual and four procedural. The differences between the conditions was the order the lessons were received in. The results were analyzed quantitatively and where there were significant effects, those results were further analyzed from a qualitative perspective. Quantitative results indicated that there was a significant time × group interaction for conceptual knowledge. The Iterative condition significantly outperformed the Concepts-first and the Procedures-first conditions. While there was no main effect of condition on procedural knowledge, SCK, and transfer, there was a main effect of time for all three of these knowledge types. Furthermore, qualitative analyses revealed that the pathway of conceptual knowledge acquisition was affected by lesson sequencing. Finally, limitations, future research, and practical implications of this study are discussed
Effects of Interfacial Energetics on the Effective Surface Recombination Velocity of Si/Liquid Contacts
Photoconductivity decay data have been obtained for NH_4F_((aq))-etched Si(111) and for air-oxidized Si(111) surfaces in contact with solutions of methanol, tetrahydrofuran (THF), or acetonitrile containing either ferrocene^(+/0) (Fc^(+/0)), [bis(pentamethylcyclopentadienyl)iron]^(+/0) (Me_(10)Fc^(+/0)), iodine (I_2), or cobaltocene^(+/0) (CoCp_2^(+/0)). Carrier decay measurements were made under both low-level and high-level injection conditions using a contactless rf photoconductivity decay apparatus. When in contact with electrolyte solutions having either very positive (Fc^(+/0), I_2/I^-) or relatively negative (CoCp_2^(+/0)) Nernstian redox potentials with respect to the conduction-band edge of Si, Si surfaces exhibited low effective surface recombination velocities. In contrast, surfaces that were exposed only to N_2(g) ambients or to electrolyte solutions that contained a mild oxidant (such as Me_(10)Fc^(+/0)) showed differing rf photoconductivity decay behavior depending on their different surface chemistry. Specifically, surfaces that possessed Si−OCH_3 bonds, produced by reaction of H-terminated Si with CH_3OH−Fc^(+/0), showed lower surface recombination velocities in contact with N_(2(g)) or in contact with CH_3OH−Me_(10)Fc^(+/0) solutions than did NH_4F_((aq))-etched, air-exposed H-terminated Si(111) surfaces in contact with the same ambients. Furthermore, the CH_3OH−Fc^(+/0)-treated surfaces showed lower surface recombination velocities than surfaces containing Si−I bonds, which were formed by the reaction of H-terminated Si surfaces with CH_3OH−I_2 or THF−I_2 solutions. These results can all be consistently explained through reference to the electrochemistry of Si/liquid contacts. In conjunction with prior measurements of the near-surface channel conductance for p^+−n−p^+ Si structures in contact with CH_3OH−Fc^(+/0) solutions, the data reveal that formation of an inversion layer (i.e., an accumulation of holes at the surface) on n-type Si, and not a reduced density of surface electrical trap sites, is primarily responsible for the long charge carrier lifetimes observed for Si surfaces in contact with CH_3OH or THF electrolytes containing I_2 or Fc^(+/0). Similarly, formation of an accumulation layer (i.e., an accumulation of electrons at the surface) consistently explains the low effective surface recombination velocity observed for the Si/CH_3OH−CoCp_2 and Si/CH_3CN−CoCp_2 contacts. Detailed digital simulations of the photoconductivity decay dynamics for semiconductors that are in conditions of inversion or depletion while in contact with redox-active electrolytes support these conclusions
A longitudinal pilot study on cognition and cerebral hemodynamics in a mouse model of preeclampsia superimposed on hypertension : looking at mothers and their offspring
Preeclampsia is a common hypertensive disorder in pregnant women and whose
causes and consequences have focused primarily on cardiovascular outcomes on the
mother and offspring, often without taking into consideration the possible effects on
the brain. One possible cause of preeclampsia has been attributed to alterations in
the renin-angiotensin system, which has also been linked to cognitive decline. In this
pilot study, we use a transgenic mouse model that chronically overexpresses human
angiotensinogen and renin (R+A
+ mice) that displayed characteristics of preeclampsia
such as proteinuria during gestation. Offspring of these mothers as well as from
control mothers were also examined. We were primarily interested in detecting whether
cognitive deficits were present in the mothers and offspring in the long term and used
a spatial learning and memory task as well as an object recognition task at three
timepoints: 3, 8, and 12 months post-partum or post-natal, while measuring blood
pressure and performing urine analysis after each timepoint. While we did not find
significant deficits in preeclamptic mothers at the later timepoints, we did observe
negative consequences in the pups of R+A
+ mice that coincided with hemodynamic
alterations whereby pups had higher whisker-evoked oxygenated hemoglobin levels and
increased cerebral blood flow responses compared to control pups. Our study provides
validation of this preeclampsia mouse model for future studies to decipher the underlying
mechanisms of long-term cognitive deficits found in offspring
Electrospun Carbon Nanofiber Webs with Controlled Density of States for Sensor Applications
Electrospun carbon nanofiber (CNF) webs with controlled density of states (DOS) are synthesized through varying the carbonization conditions to manipulate the concentration of nanosized graphite domains. These materials exhibit adjustable electrochemical activity and biosensitivity: both electron transfer kinetics for various redox systems and direct electron transfer efficiencies with enzymes increase with the DOS of the CNF webs.United States. Dept. of Energ
The time course of recognition memory impairment and glial pathology in the hAPP-J20 mouse model of Alzheimer’s disease
The role of cellular changes in the neurovascular unit is increasingly being investigated to understand the pathogenesis of Alzheimer’s disease (AD). The aim of the current study was to determine the time course of recognition memory impairment in the J20 mouse model of AD, in relation to neuroinflammatory responses and the pathology of amyloid-β (Aβ). Male hAPP-J20 and wild-type mice were assessed at 3, 6, 9, and 12 months of age. The spontaneous object recognition (SOR) task provided a measure of memory, with assessment of both a short delay (1 min) and a long delay (4 h). Immunohistochemistry was used to characterize Aβ deposition, and quantify astrocyte and microglial responses. At all ages tested, J20 mice had impaired long-term, but preserved short-term, recognition memory. Wild-types demonstrated preserved long-term memory up to 9 months of age, and preserved short-term memory at all ages tested. Plaque pathology in the J20 mice was present from 6 months onwards, with co-localization of reactive microglia and activated astrocytes. Reactive microglia and astrocyte activation in the hippocampus were significantly greater in the J20 mice at 9 months, compared to wild-types. This study contributes to our understanding of the pathological and cognitive mechanisms at play in AD. J20 mice showed impairment in retaining information over longer periods from an early age, preceding the deposition of Aβ and glial activation. Defining early physiological changes in relation to cognitive decline could provide insight into new therapeutic targets early in the disease process, when intervention is most likely to effectively slow disease progression
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