Reported Progress under the Student Right-to-Know Act: How Reliable is It?

The Student Right-to-Know Act requires colleges to provide institution-specific information on graduation rates for students initially enrolling full-time in the fall term. Not all students enroll in that fashion, especially at two-year institutions. We use data on degree-seeking students from the 1996/2001 Beginning Post-Secondary Survey to identify students for whom statistics are and are not reportable under the Act and to track their progress. Results indicate the published progress rates are substantially higher than the progress rates for the non-reportable populations, whether students enter a two-year or a four-year institution. While progress rates for the two samples are significantly correlated within four-year institutions, they are not within two-year institutions. For those beginning at two-year institutions, the progress rates reported under the Student Right-to-Know Act are indicative of neither their absolute nor their relative (cross-institution) probability of success. Policy makers and prospective students will not make efficient decisions without better information.Efficiency, Resource Allocation, Graduation

A single structured light beam as an atomic cloud splitter

We propose a scheme to split a cloud of cold non-interacting neutral atoms based on their dipole interaction with a single structured light beam which exhibits parabolic cylindrical symmetry. Using semiclassical numerical simulations, we establish a direct relationship between the general properties of the light beam and the relevant geometric and kinematic properties acquired by the atomic cloud as its passes through the beam.Comment: 10 pages, 5 figure

On the mechanism of protein fold-switching by a molecular sensor

Alternate frame folding (AFF) is a mechanism by which conformational change can be engineered into a protein. The protein structure switches from the wild-type fold (N) to a circularly-permuted fold (N\u27), or vice versa, in response to a signaling event such as ligand binding. Despite the fact that the two native states have similar structures, their interconversion involves folding and unfolding of large parts of the molecule. This rearrangement is reported by fluorescent groups whose relative proximities change as a result of the order-disorder transition. The nature of the conformational change is expected to be similar from protein to protein; thus, it may be possible to employ AFF as a general method to create optical biosensors. Toward that goal, we test basic aspects of the AFF mechanism using the AFF variant of calbindin D(9k). A simple three-state model for fold switching holds that N and N\u27 interconvert through the unfolded state. This model predicts that the fundamental properties of the switch--calcium binding affinity, signal response (i.e., fluorescence change upon binding), and switching rate--can be controlled by altering the relative stabilities of N and N\u27. We find that selectively destabilizing N or N\u27 changes the equilibrium properties of the switch (binding affinity and signal response) in accordance with the model. However, kinetic data indicate that the switching pathway does not require whole-molecule unfolding. The rate is instead limited by unfolding of a portion of the protein, possibly in concert with folding of a corresponding region

Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States

Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-β (1A.2), H1pdm (1A.3.3.2), H1-γ (1A.3.3.3), H1-δ1 (1B.2.2), and H1-δ2 (1B.2.1) currently circulating in pigs in the United States. The δ1-viruses diversified into two new genetic clades, H1-δ1a (1B.2.2.1) and H1-δ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-δ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission

Subtleties on energy calculations in the image method

In this pedagogical work we point out a subtle mistake that can be done by undergraduate or graduate students in the computation of the electrostatic energy of a system containing charges and perfect conductors if they naively use the image method. Specifically, we show that the naive expressions for the electrostatic energy for these systems obtained directly from the image method are wrong by a factor 1/2. We start our discussion with well known examples, namely, point charge-perfectly conducting wall and point charge-perfectly conducting sphere and then proceed to the demonstration of general results, valid for conductors of arbitrary shapes.Comment: 9 pages, 2 figures; Major change in this version: subsection added to Sect.4 (theorem generalization). Minor changes: title replaced; corrections to the English; some explanatory comments adde

Geographical variation in certification rates of blindness and sight impairment in England, 2008-2009

To examine and interpret the variation in the incidence of blindness and sight impairment in England by PCT, as reported by the Certificate of Vision Impairment (CVI). Design: Analysis of national certification data. Setting: All Primary Care Trusts, England. Participants: 23 773 CVI certifications issued from 2008 to 2009. Main Outcome measures: Crude and Age standardised rates of CVI data for blindness and sight loss by PCT. Methods: The crude and age standardised CVI rates per 100 000 were calculated with Spearman's rank correlation used to assess whether there was any evidence of association between CVI rates with Index of Multiple Deprivation (IMD) and the Programme Spend for Vision. Results: There was high-level variation, almost 11-fold (coefficient of variation 38%) in standardised CVI blindness and sight impairment annual certification rates across PCTs. The mean rate was 43.7 and the SD 16.7. We found little evidence of an association between the rate of blindness and sight impairment with either the IMD or Programme Spend on Vision. Conclusions: The wide geographical variation we found raises questions about the quality of the data and whether there is genuine unmet need for prevention of sight loss. It is a concern for public health practitioners who will be interpreting these data locally and nationally as the CVI data will form the basis of the public health indicator ‘preventable sight loss’. Poor-quality data and inadequate interpretation will only create confusion if not addressed adequately from the outset. There is an urgent need to address the shortcomings of the current data collection system and to educate all public health practitioners

Is Creutzfeldt-Jakob disease transmitted in blood?

Creutzfeldt-Jakob disease (CJD) has been considered infectious since the mid-1960s, but its transmissibility through the transfusion of blood or blood products is controversial. The causative agent's novel undefined nature and resistance to standard decontamination, the absence of a screening test, and the recognition that even rare cases of transmission may be unacceptable have led to the revision of policies and procedures worldwide affecting all facets of blood product manufacturing from blood collection to transfusion. We reviewed current evidence that CJD is transmitted through blood

Functional food awareness and perceptions in relation to information sources in older adults

BACKGROUND: The functional food industry has experienced innovative and economic expansion, yet research into consumer perceptions of functional foods and their associated health claims is limited. Among consumers, older adults could benefit from functional foods due to age-related issues pertaining to food and health. The purpose of this research was to identify the need for information related to functional foods among older adults (≥60 years old) and to assess awareness and perceptions of health claims on functional food packages. METHODS: Community-dwelling older adults (n = 200) completed a researcher administered questionnaire designed to collect information about functional foods including current consumption, motivating factors for consumption, perceived need for information, sources of information for functional foods and awareness of health claims. RESULTS: Prevalence of functional food consumption among participants was 93.0%. Increased awareness and knowledge was the most commonly reported factor that would promote functional food consumption (85.5%) and 63.5% of participants wanted more information about functional foods with preferred sources being newspapers/magazines/books (68.5%) and food labels (66.1%). Participants were predominately (93.5%) aware of health claims on functional foods and those with more education were more likely to report being aware of health claims (p = 0.045). CONCLUSIONS: Although functional food consumption among older adults in this sample is high, there is a need for further information regarding functional foods. These results inform stakeholders regarding the potential for information to influence functional food acceptance among older adult consumers