2,538 research outputs found

    Depression in Black Men: One Church’s Solution

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    This dissertation examines the Black Church’s influence on Pentecostal African-American men who are depressed, and how the church may assist these men to heal from the wounds of despair through a Pentecostal experience. While many Pentecostal African-American men have matriculated through the ranks of leadership, establishing successful businesses, churches, ministries, and organizational denominations; they are teetering on the edge of an emotional and spiritual breakdown. Researchers have found that African-American men are understudied and underdiagnosed as it pertains to depression. Eight African-American Pentecostal men were interviewed and given questionnaires to examine how depression affected them while maintaining leadership roles in their perspective places. After implementing a research-based intervention, participants explained their understanding and epiphanies regarding depression in men. The themes that emerged from this project were that men lacked an understanding of depression, were often in denial about their own depressed state and didn\u27t know where to access help (i.e., available resources and counseling tools). This study implies that Black men need more education and developmental programs that build their awareness of what depression looks like and how to address depression in Black men. Additionally, African-American men could particularly benefit from structures and programs that provide hands-on mentors for men that are struggling with depression. Future studies might include how to build programs within Pentecostal Black Churches that help Black men struggling with depression, along with identifying best practices for interventions located within communities of faith, particularly for men in leadership roles within the church

    The Effects of Domain Knowledge and Scene Content on Change Detection Using a Change Blindness Paradigm

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    This thesis was designed to determine how domain knowledge or scene content affects change detection. Twenty-four participants of medical professionals and non-medical professionals performed a change detection task using a flicker paradigm intended to be similar to saccadic movements or blinks. Each participant viewed 24 pictures on a computer screen, each picture flickering with a blank gray screen alternating between the original and modified version of the picture, and was asked to indicate when a change was detected by depressing a key. Twelve of the pictures were medical X-rays while the other 12 were everyday scenes. Reaction time, number of trials exceeding the 60 seconds allowed for the task, and response accuracy were measured. Results indicated that domain knowledge did not have a significant effect on the speed, number of trials exceeding time limit, or accuracy of the change detection task. However, results indicated that scene content did have a significant effect on reaction time, as all participants detected change quicker in the X-rays than in the everyday scenes. Scene content did not have an effect on response accuracy

    Conductivity of 2D many-component electron gas, partially-quantized by magnetic field

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    The 2D semimetal consisting of heavy holes and light electrons is studied. The consideration is based on assumption that electrons are quantized by magnetic field while holes remain classical. We assume also that the interaction between components is weak and the conversion between components is absent. The kinetic equation for holes colliding with quantized electrons is utilized. It has been stated that the inter-component friction and corresponding correction to the dissipative conductivity σxx\sigma_{xx} {\it do not vanish at zero temperature} due to degeneracy of the Landau levels. This correction arises when the Fermi level crosses the Landau level. The limits of kinetic equation applicability were found. We also study the situation of kinetic memory when particles repeatedly return to the points of their meeting.Comment: 13 pages, 1 figur

    Hypospadias and endocrine disruption: is there a connection?

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    Hypospadias is one of the most common congenital anomalies in the United States, occurring in approximately 1 in 250 newborns or roughly 1 in 125 live male births. It is the result of arrested development of the urethra, foreskin, and ventral surface of the penis where the urethral opening may be anywhere along the shaft, within the scrotum, or in the perineum. The only treatment is surgery. Thus, prevention is imperative. To accomplish this, it is necessary to determine the etiology of hypospadias, the majority of which have been classified as idiopathic. In this paper we briefly describe the normal development of the male external genitalia and review the prevalence, etiology, risk factors, and epidemiology of hypospadias. The majority of hypospadias are believed to have a multifactorial etiology, although a small percentage do result from single gene mutations. Recent findings suggest that some hypospadias could be the result of disrupted gene expression. Discoveries about the antiandrogenic mechanisms of action of some contemporary-use chemicals have provided new knowledge about the organization and development of the urogenital system and may provide additional insight into the etiology of hypospadias and direction for prevention

    Physiological Epicotyl Dormancy and Recalcitrant Storage Behaviour in Seeds of Two Tropical Fabaceae (Subfamily Caesalpinioideae) Species

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    BACKGROUND AND AIMS: Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. METHODOLOGY: Fresh seeds were (i) dried to various moisture levels, and (ii) stored at -1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. PRINCIPAL RESULTS: FRESH SEEDS OF BOTH SPECIES HAD HIGH MOISTURE CONTENT (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at -1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them inHowever, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ∼30-35 days in B. coccinea seeds. CONCLUSIONS: Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is C(nd) (root)-[Formula: see text] (epicotyl)

    Metastatic pulmonary calcification

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    Metastatic pulmonary calcification (MPC) may develop in patients with secondary hyperparathyroidism, related to end-stage renal disease (ESRD).1 The histologic pulmonary findings show calcium deposition in the lung interstitium, alveolar septa and bronchial walls.2 We present a patient with CT findings of MPC that resolved with medical treatment for secondary hyperparathyroidism. To our knowledge, complete resolution of metastatic pulmonary calcification following treatment has not been previously described in the literature

    On the effect of far impurities on the density of states of two-dimensional electron gas in a strong magnetic field

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    The effect of impurities situated at different distances from a two-dimensional electron gas on the density of states in a strong magnetic field is analyzed. Based on the exact result of Brezin, Gross, and Itzykson, we calculate the density of states in the whole energy range, assuming the Poisson distribution of impurities in the bulk. It is shown that in the case of small impurity concentration the density of states is qualitatively different from the model case when all impurities are located in the plane of the two-dimensional electron gas.Comment: 6 pages, 1 figure, submitted to JETP Letter

    Photon gating in four-dimensional ultrafast electron microscopy

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    Ultrafast electron microscopy (UEM) is a pivotal tool for imaging of nanoscale structural dynamics with subparticle resolution on the time scale of atomic motion. Photon-induced near-field electron microscopy (PINEM), a key UEM technique, involves the detection of electrons that have gained energy from a femtosecond optical pulse via photon–electron coupling on nanostructures. PINEM has been applied in various fields of study, from materials science to biological imaging, exploiting the unique spatial, energy, and temporal characteristics of the PINEM electrons gained by interaction with a “single” light pulse. The further potential of photon-gated PINEM electrons in probing ultrafast dynamics of matter and the optical gating of electrons by invoking a “second” optical pulse has previously been proposed and examined theoretically in our group. Here, we experimentally demonstrate this photon-gating technique, and, through diffraction, visualize the phase transition dynamics in vanadium dioxide nanoparticles. With optical gating of PINEM electrons, imaging temporal resolution was improved by a factor of 3 or better, being limited only by the optical pulse widths. This work enables the combination of the high spatial resolution of electron microscopy and the ultrafast temporal response of the optical pulses, which provides a promising approach to attain the resolution of few femtoseconds and attoseconds in UEM

    Two regimes for effects of surface disorder on the zero-bias conductance peak of tunnel junctions involving d-wave superconductors

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    Impurity-induced quasiparticle bound states on a pair-breaking surface of a d-wave superconductor are theoretically described, taking into account hybridization of impurity- and surface-induced Andreev states. Further a theory for effects of surface disorder (of thin impurity surface layer) on the low-bias conductance of tunnel junctions is developed. We find a threshold ncn_c for surface impurity concentration nSn_S, which separates the two regimes for surface impurity effects on the zero-bias conductance peak (ZBCP). Below the threshold, surface impurities do not broaden the ZBCP, but effectively reduce its weight and generate impurity bands. For low nSn_S impurity bands can be, in principle, resolved experimentally, being centered at energies of bound states induced by an isolated impurity on the surface. For larger nSn_S impurity bands are distorted, move to lower energies and, beginning with the threshold concentration nS=ncn_S=n_c, become centered at zero energy. With increasing nSn_S above the threshold, the ZBCP is quickly destroyed in the case of strong scatterers, while it is gradually suppressed and broaden in the presence of weak impurity potentials. More realistic cases, taking into account additional broadening, not related to the surface disorder, are also considered.Comment: 9 pages, 7 figure

    Why Large Seeds with Physical Dormancy Become Nondormant Earlier Than Small Ones

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    Under natural conditions, large seeds with physical dormancy (PY) may become water permeable earlier than small ones. However, the mechanism for this difference has not been elucidated. Thus, our aim was to evaluate the traits associated with PY in seeds of Senna multijuga (Fabaceae) and to propose a mechanism for earlier dormancy-break in large than in small seeds. Two seedlots were collected and each separated into large and small seeds. Seed dry mass, water content, thickness of palisade layer in the hilar and distal regions and the ratio between palisade layer thickness (P) in the lens fissure and seed mass (M) were evaluated. Further, the correlation between seed mass and seed dimensions was investigated. Large seeds had higher dry mass and water content than small seeds. The absolute thickness of the palisade layer in the different regions did not show any trend with seed size; however, large seeds had a lower P:M ratio than small seeds. Seed mass correlated positively with all seed dimensions, providing evidence for a substantially higher volume in large seeds. Since wet, but not dry, high temperatures break PY in sensitive seeds of S. multijuga, the data support our prediction that internal pressure potential in the seed and palisade layer thickness in the water gap (lens), which is related to seed mass (i.e. P:M ratio), act together to modulate the second step (dormancy break) of the two-stage sensitivity cycling model for PY break. In which case, large seeds are predetermined to become water-permeable earlier than small ones
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