5,939 research outputs found
Effects of Microbiota on Starvation Resistant Drosophila Melanogaster
Bacteria in modern society have often been perceived as having negative effects on humans with complications and potential death to their hosts. In recent years, the gut microbiota has shown that not all bacteria inhabiting a host cause negative side effects, but they instead can provide essential nutrients to their host and even directly impact growth rate and development. In this study, axenic Drosophila melanogaster were generated through egg dechorionation with 7% bleach to test the effects of the absence of commensal bacteria on the flies growth and development. Lipid content was recorded of control and axenic fruit flies from six different populations: FA, FB, FC, SA, SB, SC. On average, the axenic flies took approximately three days longer to development compared to the control. Starvation resistant axenic flies that survived had lower lipid content compared to their control counterparts
The therapeutic effects of Millon Clinical Multiaxial Inventory-III assessment feedback
A study was conducted to test the therapeutic effects of assessment feedback on rapport-building and self-enhancement variables (self-verification, self-discovery, self-esteem), as well as symptomatology. Assessment feedback was provided in the form of interpretive information based on the results of the Millon Clinical Multiaxial Inventory- III (MCMI-III). Participants (N = 89) were randomly assigned to three groups: a Feedback group, a Reflective-Counseling group, and a No-Feedback group. The Feedback group was provided with assessment feedback, the Reflective-Counseling group was asked to comment on the meaning of the taking the MCMI-III, the No- Feedback group received general information about the MCMI-III. Results revealed that assessment feedback, when provided in the form of interpretive interpretation positively affects rapport-building and self-enhancement variables (self-verification and self-discovery). No significant results were found in terms of self-esteem or symptom decrease as a function of feedback. However, a significant decrease in symptoms across groups was found. Results indicate that assessment feedback in the form of interpretive information can be used as a starting point in therapy. Implications of the findings are discussed with respect to theory and clinical practice
Clustering and gelation of hard spheres induced by the Pickering effect
A mixture of hard-sphere particles and model emulsion droplets is studied
with a Brownian dynamics simulation. We find that the addition of nonwetting
emulsion droplets to a suspension of pure hard spheres can lead to both
gas-liquid and fluid-solid phase separations. Furthermore, we find a stable
fluid of hard-sphere clusters. The stability is due to the saturation of the
attraction that occurs when the surface of the droplets is completely covered
with colloidal particles. At larger emulsion droplet densities a percolation
transition is observed. The resulting networks of colloidal particles show
dynamical and mechanical properties typical of a colloidal gel. The results of
the model are in good qualitative agreement with recent experimental findings
[E. Koos and N. Willenbacher, Science 331, 897 (2011)] in a mixture of
colloidal particles and two immiscible fluids.Comment: 5 figures, 5 page
Computer simulations of colloidal transport on a patterned magnetic substrate
We study the transport of paramagnetic colloidal particles on a patterned
magnetic substrate with kinetic Monte Carlo and Brownian dynamics computer
simulations. The planar substrate is decorated with point dipoles in either
parallel or zigzag stripe arrangements and exposed to an additional external
magnetic field that oscillates in time. For the case of parallel stripes we
find that the magnitude and direction of the particle current is controlled by
the tilt angle of the external magnetic field. The effect is reliably obtained
in a wide range of ratios between temperature and magnetic permeability.
Particle transport is achieved only when the period of oscillation of the
external field is greater than a critical value. For the case of zigzag stripes
a current is obtained using an oscillating external field normal to the
substrate. In this case, transport is only possible in the vertex of the
zigzag, giving rise to a narrow stream of particles. The magnitude and
direction of the particle current are found to be controlled by a combination
of the zigzag angle and the distance of the colloids from the substrate.
Metropolis Monte Carlo and Brownian dynamics simulations predict results that
are in good agreement with each other. Using kinetic Monte Carlo we find that
at high density the particle transport is hindered by jamming.Comment: 8 pages, 9 figure
NAVIGATING THE CAREER PIPELINE: EXPERIENCES OF FEMALE COMMUNITY COLLEGE PRESIDENTS
Despite holding a majority of lower and middle management positions in public two-year institutions, women still hold only one-third of current community college presidencies. This study explored the gendered phenomenon of navigating the career pipeline in higher education to reach the office of community college president. The purpose of the study was to examine the educational backgrounds and career paths of recently-appointed female community college presidents, as well as the barriers and sources of support they encountered while navigating the career pipeline.
A phenomenological approach was utilized for this qualitative study. Data was primarily collected using semi-structured interviews. Additional sources for data collection include reflection logs, memos, and document analysis. A modified van Kaam method of data analysis was used to code participant data and identify recurring thematic elements. These recurring thematic elements provided the foundation for individual descriptions of the phenomenon, which were later synthesized to create a composite description.
Results suggest that study participants encountered three types of barriers while navigating the career pipeline in higher education: institutional, birdcage, and internal. The term “birdcage barriers” was coined here to describe scenarios in which aspiring female leaders could identify opportunities for professional growth or advancement, but were unable to access these opportunities because of situational boundaries. Findings also suggest study participants benefited from three sources of support: institutional, personal, and individual traits/strategies. Additional findings include: participants were reluctant to label gender a barrier; most of the institutional bias encountered by participants was second-generation; and, as aspiring leaders in higher education, participants required intrusive recruitment
Policing Alcohol and Related Crimes On Campus
Research shows that college students drink alcohol frequently and heavily. This can compromise their health and well-being. Student drinking is also tied to crime. While prior work explores the nature and extent of crimes involving alcohol on campus, to date no study has examined how police handle these incidents or crime generally. This study fills that gap in the literature. Qualitative and quantitative data were collected by observing and interviewing campus officers at a large Southeastern university as they navigated through encounters with citizens. Findings include the following. Officers handle a variety of crimes, and do not have a single-faceted view of what makes one offense more serious than another. Traffic stops were the most frequent reason that officers encountered suspects. Alcohol incidents accounted for nearly one in three police-citizen encounters. In traffic stops and alcohol incidents, officers tended to sanction suspects leniently; participants\u27 explanations of this varied. Only a few suspects were arrested because of their offenses; the major reasons for this are the seriousness of the crimes, legal mandate, and suspects\u27 demeanor. Implications for policy are discussed
Average Shortest Path Length in a Novel Small-World Network
We study a novel model of random graph which exhibits the structural characteristics of the Watts- Strogatz small-world network. The small-world network is characterized by a high level of local clustering while also having a relatively small graph diameter. The same behavior that makes the Watts-Strogatz model behave like this also makes it difficult to analyze. Our model addresses this issue, closely mimicking the same structure experimentally while following a constructive process that makes it easier to analyze mathematically. We present a bound on the average shortest path length in our new model, which we approach by looking at the two key geometric components
Activated dynamics and effective temperature in a steady state sheared glass
We conduct nonequilibrium molecular dynamics simulations to measure the shear
stress, the average inherent structure energy, and the effective temperature
of a sheared model glass as a function of bath temperature and
shear strain rate. For above the glass transition temperature , the
rheology approaches a Newtonian limit and approaches as the
strain rate approaches zero, while for , the shear stress approaches a
yield stress and approaches a limiting value near . In the
shear-dominated regime at high , high strain rate or at low , we find
that the shear stress and the average inherent structure energy each collapse
onto a single curve as a function of . This indicates that
is controlling behavior in this regime.Comment: 4 pages, 2 figures. Revised to include additional data. Inherent
structure energy results were included, and much of the shear transformation
zone discussion was remove
Malaria-filaria coinfection in mice makes malarial disease more severe unless filarial infection achieves patency
Coinfections are common in natural populations, and the literature suggests that helminth coinfection readily affects how the immune system manages malaria. For example, type 1–dependent control of malaria parasitemia might be impaired by the type 2 milieu of preexisting helminth infection. Alternatively, immunomodulatory effects of helminths might affect the likelihood of malarial immunopathology. Using rodent models of lymphatic filariasis (Litomosoides sigmodontis) and noncerebral malaria (clone AS Plasmodium chabaudi chabaudi), we quantified disease severity, parasitemia, and polyclonal splenic immune responses in BALB/c mice. We found that coinfected mice, particularly those that did not have microfilaremia (Mf), had more severe anemia and loss of body mass than did mice with malaria alone. Even when controlling for parasitemia, malaria was most severe in Mf coinfected mice, and this was associated with increased interferon-g responsiveness. Thus, in Mf mice, filariasis upset a delicate immunological balance in malaria infection and exacerbated malaria-induced immunopathology. Helminth infections are prevalent throughout tropical regions where malaria is transmitted [1–5]. Interactions among infections commonly alter disease severity [6, 7], and malaria-helminth coinfection can either exac
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