Publications by authors named "Walcott C"

Article Synopsis
  • The article DOI: 10.3389/fimmu.2021.641188 has been identified as needing corrections.
  • These corrections aim to address inaccuracies or clarify points within the original publication.
  • Readers are encouraged to refer to the updated version for the most accurate information.
View Article and Find Full Text PDF
Article Synopsis
  • Lymphocyte migration is essential for immune surveillance and requires precise regulation by chemokines and their receptors.
  • Protein geranylgeranylation, a post-translational modification, is vital for proper signaling of chemokine receptors and influences T cell movement and function.
  • Deficiency in protein geranylgeranylation hampers thymocyte egress, affects T cell homing, alters T helper cell differentiation, and provides resistance to autoimmune conditions in specific mouse models.
View Article and Find Full Text PDF

In the early 1970s, Floriano Papi and colleagues proposed the olfactory-navigation hypothesis, which explains the homing ability of pigeons by the existence of an odor-based map acquired through learning. This notion, although supported by some observations, has also generated considerable controversy since its inception. As an alternative, Paulo Jorge and colleagues formulated in 2009 the olfactory-activation hypothesis, which states that atmospheric odorants do not provide navigational information but, instead, activate a non-olfactory path integration system.

View Article and Find Full Text PDF

Sickle cell trait (SCT) places individuals at risk of passing an abnormal hemoglobin gene to biological children and is associated with rare but serious complications. The present study sought to examine knowledge of SCT and awareness of personal trait status among 258 young African American adults. Participants were surveyed regarding demographics, medical history, and sources of sickle cell information before completing a trait knowledge questionnaire.

View Article and Find Full Text PDF

Background: The aims of this study were to describe guardian perceptions of the experiences of a sample of youth with sickle cell disease (SCD) in rural emergency departments (EDs) with a focus on overall patient satisfaction and characteristics of care.

Procedure: Guardians of 139 children with SCD (0 to 17 y) seen at a rural pediatric SCD clinic completed a survey concerning their children's ED experiences in the past 6 months, including information about ED wait times, quality of communications and interactions with the ED health care providers, pain management, perceptions of speed of care, and overall satisfaction.

Results: About 41% of guardians reported that their child visited the ED in the past 6 months.

View Article and Find Full Text PDF

Methods for measuring homework performance have been limited primarily to parent reports of homework deficits. The Homework Performance Questionnaire (HPQ) was developed to assess the homework functioning of students in Grades 1 to 8 from the perspective of both teachers and parents. The purpose of this study was to examine the factorial validity of teacher and parent versions of this scale, and to evaluate gender and grade-level differences in factor scores.

View Article and Find Full Text PDF

Background: Youth with sickle cell disease (SCD) are at higher risk for grade retention than healthy peers. This is salient because research suggests grade retention is ineffective and places youth at additional risk for negative outcomes. The aims of the present study were to identify possible risk factors for grade retention in youth with SCD and to examine positive family functioning as a possible resilience factor.

View Article and Find Full Text PDF

Objective: The link between significant attention problems and reading difficulties among school-age children is clear, but few have examined the impact of early inattention on preliteracy development. This longitudinal study examines this link.

Method: A total of 47 children had repeated measures of teacher-rated attention problems and three key preliteracy skills (phonemic awareness, letter knowledge, and rapid naming) in both preschool and kindergarten.

View Article and Find Full Text PDF

1. The concept that animals benefit from gaining familiarity with physical spaces is widespread among ecologists and constitutes a theoretical pillar in studies of territory defence, philopatry and habitat selection. Yet proximate causes and fitness benefits of site familiarity are poorly known.

View Article and Find Full Text PDF

Artificial manipulations of habitat, such as those that incorporate adding nesting boxes or platforms for birds, often enhance the breeding success of threatened animals. However, such alterations are likely to have unintended behavioral and ecological effects that might negatively impact the target species or others in its community. We conducted a controlled study to investigate the effect of artificial nesting platforms on aggressive behavior and reproductive success of male common loons (Gavia immer).

View Article and Find Full Text PDF

How homing pigeons displaced into unfamiliar territory find their way home has been the subject of extensive experimentation and debate. One reason for the controversy is that pigeons seem to use multiple cues. Clock-shifting experiments show that experienced pigeons use the sun as a preferred compass; when it is not available they rely on magnetic cues.

View Article and Find Full Text PDF

This study examined group differences of 49 boys ages 6 to 11 years with and without attention deficit hyperactivity disorder (ADHD) in emotion regulation during frustrating peer competition. Half of all boys in each group were explicitly instructed to hide their feelings if they became upset during the competition. Behavioral inhibition, both before and after the competitive task, was examined using the Stop Signal Task (SST), and emotion regulation was assessed via structured observation data.

View Article and Find Full Text PDF

Eighteen monohydroxy polycyclic aromatic hydrocarbon metabolites (OH-PAHs) representing polycyclic aromatic hydrocarbons (PAHs) containing up to four rings in human urine have been measured. The method includes the addition of carbon-13 labeled internal standards, enzymatic hydrolysis, and solid-phase microextraction followed by gas chromatography with high-resolution mass spectrometry. By using response factors calculated with the carbon-13 labeled standards, results are presented for calibration, relative standard deviations and analyte levels from an unspiked human urine pool.

View Article and Find Full Text PDF

For measurement of biomarkers from polycyclic aromatic hydrocarbon (PAH) exposure, an analytical method is described quantifying hydroxylated PAH (OH-PAH) in urine samples. This method determined monohydroxy metabolites of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, benzo[c]phenanthrene, and benz[a]anthracene. The sample preparation consisted of enzymatic hydrolysis, solid-phase extraction and derivatization with a silylating reagent.

View Article and Find Full Text PDF

Homing pigeons can return from distant, unfamiliar release points. Experienced pigeons can do so even if they are transported anesthetized and deprived of outward journey information. Airplane tracking has shown that they make relatively straight tracks on their homeward journey; therefore, pigeons must have some way of determining the home direction at the release site.

View Article and Find Full Text PDF

The homing of racing pigeons is often slowed down on days of high sun-spot activity or variability in the earth's magnetic field. The orientation of Ring-billed Gull chicks as well as the vanishing bearings of homing pigeons also seem to change in response to variability in the earth's magnetic field. Furthermore, homing pigeons released under sunny skies at locations where the earth's magnetic field is distributed are disoriented, yet pigeons equipped with devices that change the magnetic field around their head home normally.

View Article and Find Full Text PDF

Homing pigeons appear to use the earth's magnetic field as a compass and perhaps as part of their position-finding system or 'map'. The sensory system they use to detect magnetic fields is unknown, but two current possibilities are some mode of response by the pineal organ or by the visual system, or it may be based on the magnetite crystals found in their heads. Three series of experiments to test the involvement of magnetite are reported here.

View Article and Find Full Text PDF

Research on pigeon homing suggests that magnetic field information is used for orientation. The ability of pigeons to sense magnetic fields may be associated with a small, unilateral structure between the brain and the skull which contains magnetic in what appears to be single domains.

View Article and Find Full Text PDF

Midair collsions between birds and aircraft pose a hazard for both. While observing migrating birds with a tracking radar, we find that birds often react, by taking evasive maneuvers, at distances of 200-300 m to both searchlight beams and the approach of a small airplane with its landing lights on. Appropriately arranged lights on aircraft should decrease the hazard of collisions with birds.

View Article and Find Full Text PDF

Homing pigeons were equipped with a pair of small coils around their heads. Birds with an induced field of 0.6 gauss and the south magnetic pole up, oriented toward home normally under both sun and overcast.

View Article and Find Full Text PDF