Random distributed feedback fiber laser

Researchers conducted investigations to demonstrate the advantages of random distributed feedback fiber laser. Random lasers had advantages, such as simple technology that did not require a precise microcavity and low production cost. The properties of their output radiation were special in comparison to those of conventional lasers and they were characterized by complex features in the spatial, spectral, and time domains. The researchers demonstrated a new type of one-dimensional laser with random distributed feedback based on Rayleigh scattering (RS) that was presented in any transparent glass medium due to natural inhomogeneities of refractive index. The cylindrical fiber waveguide geometry provided transverse confinement, while the cavity was open in the longitudinal direction and did not include any regular point-action reflectors.

Raman fiber lasers with a random distributed feedback based on Rayleigh scattering

We demonstrate lasing based on a random distributed feedback due to the Raman amplified Rayleigh backscattering in different types of cavities with and without conventional point-action reflectors. Quasistationary generation of a narrowband spectrum is achieved despite the random nature of the feedback. The generated spectrum is localized at the reflection or gain spectral maxima in schemes with and without point reflectors, respectively. The length limit for a conventional cavity and the minimal pump power required for the lasing based purely on a random distributed feedback are determined. © 2010 The American Physical Society.

College of Medicine Feedback from MSV & LCME

Notes, emails, and documents containing feedback on the LCME mock site visit.

Visual driver support system for traffic signs

It has been well documented that traffic accidents that can be avoided occur when the motorists miss or ignore traffic signs. With the attention of drivers getting diverted due to distractions like cell phone conversations, missing traffic signs has become more prevalent. Also, poor weather and other unfriendly driving conditions sometimes makes the motorists not to be alert all the time and see every traffic sign on the road. Besides, most cars do not have any form of traffic assistance. Because of heavy traffic and proliferation of traffic signs on the roads, there is a need for a system that assists the driver not to miss a traffic sign to reduce the probability of an accident. Since visual information is critical for driving, processed video signals from cameras have been chosen to assist drivers. These inexpensive cameras can be easily mounted on the automobile. The objective of the present investigation and the traffic system development is to recognize the traffic signs electronically and alert drivers. For the case study and the system development, five important and critical traffic signs have been selected. They are: STOP, NO ENTER, NO RIGHT TURN, NO LEFT TURN, and YIELD. The system was evaluated processing still pictures taken from the public roads, and the recognition results were presented in an analysis table to indicate the correct identifications and the false ones. The system reached the acceptable recognition rate of 80% for all five traffic signs. The processing rate was about three seconds. The capabilities of MATLAB, VLSI design platforms and coding have been used to generate a visual warning to complement the visual driver support system with a Field Programmable Gate Array (FPGA) on a XUP Virtex-II Pro Development System.

Effect of performance feedback on perceived knowledge and likelihood to pursue continuing education

The purpose of this study was to assess the effect of performance feedback on Athletic Trainers’ (ATs) perceived knowledge (PK) and likelihood to pursue continuing education (CE). The investigation was grounded in the theories of “the definition of the situation” (Thomas & Thomas, 1928) and the “illusion of knowing,” (Glenberg, Wilkinson, & Epstein, 1982) suggesting that PK drives behavior. This investigation measured the degree to which knowledge gap predicted CE seeking behavior by providing performance feedback designed to change PK. A pre-test post-test control-group design was used to measure PK and likelihood to pursue CE before and after assessing actual knowledge. ATs (n=103) were randomly sampled and assigned to two groups, with and without performance feedback. Two independent samples t-tests were used to compare groups on the difference scores of the dependent variables. Likelihood to pursue CE was predicted by three variables using multiple linear regression: perceived knowledge, pre-test likelihood to pursue CE, and knowledge gap. There was a 68.4% significant difference (t101=2.72, p=0.01, ES=0.45) between groups in the change scores for likelihood to pursue CE because of the performance feedback (Experimental group=13.7% increase; Control group=4.3% increase). The strongest relationship among the dependent variables was between pre-test and post-test measures of likelihood to pursue CE (F2,102=56.80, p<0.01, r=0.73, R2=0.53). The pre- and post-test predictive relationship was enhanced when group was included in the model. In this model [YCEpost=0.76XCEpre-0.34 Xgroup+2.24+E], group accounted for a significant amount of unique variance in predicting CE while the pre-test likelihood to pursue CE variable was held constant (F3,102=40.28, p<0.01, r=0.74, R2=0.55). Pre-test knowledge gap, regardless of group allocation, was a linear predictor of the likelihood to pursue CE (F1,102=10.90, p=.01, r=.31, R2=.10). In this investigation, performance feedback significantly increased participants’ likelihood to pursue CE. Pre-test knowledge gap was a significant predictor of likelihood to pursue CE, regardless if performance feedback was provided. ATs may have self-assessed and engaged in internal feedback as a result of their test-taking experience. These findings indicate that feedback, both internal and external, may be necessary to trigger CE seeking behavior.

Disturbance Driven Colony Fragmentation as a Driver of a Coral Disease Outbreak

In September of 2010, Brewer's Bay reef, located in St. Thomas (U.S. Virgin Islands), was simultaneously affected by abnormally high temperatures and the passage of a hurricane that resulted in the mass bleaching and fragmentation of its coral community. An outbreak of a rapid tissue loss disease among coral colonies was associated with these two disturbances. Gross lesion signs and lesion progression rates indicated that the disease was most similar to the Caribbean coral disease white plague type 1. Experiments indicated that the disease was transmissible through direct contact between colonies, and five-meter radial transects showed a clustered spatial distribution of disease, with diseased colonies being concentrated within the first meter of other diseased colonies. Disease prevalence and the extent to which colonies were bleached were both significantly higher on unattached colony fragments than on attached colonies, and disease occurred primarily on fragments found in direct contact with sediment. In contrast to other recent studies, disease presence was not related to the extent of bleaching on colonies. The results of this study suggest that colony fragmentation and contact with sediment played primary roles in the initial appearance of disease, but that the disease was capable of spreading among colonies, which suggests secondary transmission is possible through some other, unidentified mechanism.

Hotel Guest e-questionnaires: Implications for Feedback and Relationships

This paper examines the reliability and efficacy of hotel guest e-mail questionnaire compared to the paper questionnaire in the Asian Pacific context. Conducted inPerth,SingaporeandPenang, cities with mature hospitality and tourism industries and a representation of chain and independent deluxe hotels, this exploratory qualitative study examines hotelier views of e-mail guest communication derived from content analysis of guest questionnaires format and content and in-depth interviews with senior hoteliers. The findings indicated that e-questionnaires manifested as e-mails, as a direct replacement of the paper questionnaire, appear to be premature given divergent hotelier views and shortcomings in e-mail response administration. If properly executed, e-mail can play an increasingly important adjunct role to the paper guest questionnaire as a part of a multi-channel approach. The balance/relationship between ‘high tech’ and ‘high touch’ needs to be maintained: the latter can enhance the latter but should not undermine it.

Searching for the Holy Grail of International Education: Feedback from Hospitality Management Study Abroad Participants

This article reports on a study done among hospitality management students who participated in study abroad programs between January 2001 and May 2003. The participants in the study were both incoming students to the US and outgoing students from the US. The study investigates, among other things, why they had decided to study abroad, why they had selected a particular institution, how their home institution compared to the partner institution abroad, and what they perceived to be the benefits and relevance of their international experiences. It was found that respondents were generally very positive about the study abroad experience. Some interesting differences of opinion were found when the perceptions of the incoming students were compared to those of the outgoing students. The results of this study may be of particular interest to hospitality management administrators and faculty who create and administer international exchange programs.

The effects of goal setting and attributional feedback on self -efficacy for writing and writing achievement

This study investigated the effectiveness of goal setting and attributional feedback on self-efficacy for writing and writing achievement of students who are gifted underachievers. Students in grades 3, 4 and 5 participated. Five dependent measures were investigated: fluency, syntax, range, diversity and organization. The results indicated that a systematic writing instruction program increased self-efficacy for writing. In addition the self-efficacy strategies of goal setting and attributional feedback improve self-efficacy and increased some areas of writing achievement. The dependent measures most affected were fluency, syntax and organization. The students in this study did not improve their levels of vocabulary. This study included many practical applications for teachers to use in a classroom setting. ^

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. ^

The Influence of Vegetation on the Hydrodynamics and Geomorphology of a Tree Island in Everglades National Park (Florida, United States)

Transpiration-driven nutrient accumulation has been identified as a potential mechanism governing the creation and maintenance of wetland vegetation patterning. This process may contribute to the formation of nutrient-rich tree islands within the expansive oligotrophic marshes of the Everglades (Florida, United States). This study presents hydrogeochemical data indicating that tree root water uptake is a primary driver of groundwater ion accumulation across one of these islands. Sap flow, soil moisture, water level, water chemistry, and rainfall were measured to identify the relationships between climate, transpiration, and groundwater uptake by phreatophytes and to examine the effect this uptake has on groundwater chemistry and mineral formation in three woody plant communities of differing elevations. During the dry season, trees relied more on groundwater for transpiration, which led to a depressed water table and the advective movement of groundwater and dissolved ions, including phosphorus, from the surrounding marsh towards the centre of the island. Ion exclusion during root water uptake led to elevated concentrations of all major dissolved ions in the tree island groundwater compared with the adjacent marsh. Groundwater was predominately supersaturated with respect to aragonite and calcite in the lower-elevation woody communities, indicating the potential for soil formation. Elevated groundwater phosphorous concentrations detected in the highest-elevation woody community were associated with the leaching of inorganic sediments (i.e. hydroxyapatite) in the vadose zone. Understanding the complex feedback mechanisms regulating plant/groundwater/surface water interactions, nutrient dynamics, and potential soil formation is necessary to manage and restore patterned wetlands such as the Everglades.

Application of biomarkers and compound specific stable isotopes for the assessment of hydrology as a driver of organic matter dynamics in the Everglades ecosystem

The Everglades is a sub-tropical coastal wetland characterized among others by its hydrological features and deposits of peat. Formation and preservation of organic matter in soils and sediments in this wetland ecosystem is critical for its sustainability and hydrological processes are important divers in the origin, transport and fate of organic matter. With this in mind, organic matter dynamics in the greater Florida Everglades was studied though various organic geochemistry techniques, especially biomarkers, bulk and compound specific δ13C and δD isotope analysis. The main objectives were focused on how different hydrological regimes in this ecosystem control organic matter dynamics, such as the mobilization of particulate organic matter (POM) in freshwater marshes and estuaries, and how organic geochemistry techniques can be applied to reconstruct Everglades paleo-hydrology. For this purpose organic matter in typical vegetation, floc, surface soils, soil cores, and estuarine suspended particulates were characterized in samples selected along hydrological gradients in the Water Conservation Area 3, Shark River Slough and Taylor Slough. ^ This research focused on three general themes: (1) Assessment of the environmental dynamics and source-specific particulate organic carbon export in a mangrove-dominated estuary. (2) Assessment of the origin, transport and fate of organic matter in freshwater marsh. (3) Assessment of historical changes in hydrological conditions in the Everglades (paleo-hydrology) though biomarkes and compound specific isotope analyses. This study reports the first estimate of particulate organic carbon loss from mangrove ecosystems in the Everglades, provides evidence for particulate organic matter transport with regards to the formation of ridge and slough landscapes in the Everglades, and demonstrates the applicability of the combined biomarker and compound-specific stable isotope approach as a means to generate paleohydrological data in wetlands. The data suggests that: (1) Carbon loss from mangrove estuaries is roughly split 50/50 between dissolved and particulate carbon; (2) hydrological remobilization of particulate organic matter from slough to ridge environments may play an important role in the maintenance of the Everglades freshwater landscape; and (3) Historical changes in hydrology have resulted in significant vegetation shifts from historical slough type vegetation to present ridge type vegetation. ^

Informational effects of assessment feedback

This study tested the effects of informational assessment feedback on satisfaction, selfesteem and examiner ratings. 83 participants completed a self-report personality inventory (Millon Index of Personality Styles). Participants of the experimental group were given standardized, informational assessment. Participants in the control group received only general information about the personality inventory. Significant group differences were found for the Feedback Assessment Questionnaire with t (81) = 11.67, p

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.

The effects of audio cueing and an instructions, feedback and praise package on the distribution of teacher praise to students of differing on-task levels

In an audio cueing system, a teacher is presented with randomly spaced auditory signals via tape recorder or intercom. The teacher is instructed to praise a child who is on-task each time the cue is presented. In this study, a baseline was obtained on the teacher's praise rate and the children's on-task behaviour in a Grade 5 class of 37 students. Children were then divided into high, medium and low on-task groups. Followinq baseline, the teacher's praise rate and the children's on-task behaviour were observed under the following successively implemented conditions: (l) Audio Cueing 1: Audio cueing at a rate of 30 cues per hour was introduced into the classroom and remained in effect during subsequent conditions. A group of consistently low on-task children were delineated. (2) Audio Cueing Plus 'focus praise package': Instructions to direct two-thirds o£ the praise to children identified by the experimenter (consistently low on-task children), feedback and experimenter praise for meeting or surpassing the criterion distribution of praise ('focus praise package') were introduced. (3) Audio Cueing 2: The 'focus praise package' was removed. (4) Audio Cueing Plus 'increase praise package': Instructions to increase the rate of praise, feedback and experimenter praise for improved praise rates ('increase praise package') were introduced. The primary aims of the study were to determine the distribution of praise among hi~h, medium and low on-task children when audio cueinq was first introduced and to investigate the effect of the 'focus praise package' on the distribution of teacher praise. The teacher distributed her praise evenly among the hiqh, medium and low on-task groups during audio cueing 1. The effect of the 'focus praise package' was to increase the percentage of praise received by the consistently low on-task children. Other findings tended to suggest that audio cueing increased the teacher's praise rate. However, the teacher's praise rate unexpectedly decreased to a level considerably below the cued rate during audio cueing 2. The 'increase praise package' appeared to increase the teacher's praise rate above the audio cueing 2 level. The effect of an increased praise rate and two distributions of praise on on-task behaviour were considered. Significant increases in on-task behaviour were found in audio cueing 1 for the low on-task group, in the audio cueing plus 'focus praise package' condition for the entire class and the consistently low on-task group and in audio cueing 2 for the medium on-task group. Except for the high on-task children who did not change, the effects of the experimental manipulations on on-task behaviour were e quivocal. However, there were some indications that directing 67% of the praise to the consistently low on-task children was more effective for increasing this group's on-task behaviour than distributing praise equally among on-task groups.