Letter from the Editor

For the seventh time, the Gettysburg Historical Journal of Gettysburg College put out a call for the submissions to the annual journal, and once again, the Journal received a large number of outstanding student compositions on the topic of history. This year in particular, the editorial board faced a daunting task in deciding which submissions were the best of the best

Portrait of Philip H. Glatfelter in Glatfelter Hall

The first floor lobby of Glatfelter Hall is home to a Ned Bittinger oil painting portrait of Philip H. Glatfelter, the namesake of the building. Bittinger was commissioned in 1988 to paint the portraits of several Gettysburg College benefactors. Philip H. Glatfelter’s generosity to Gettysburg College was never ending. In a forty year period, P.H. Glatfelter, his son William L. Glatfelter, and their immediate family gave $225,000 to Gettysburg College. At the time of his death in 1907, he was considered “one of the best friends, if not the best, that Gettysburg College ever had.” [excerpt] Course Information: Course Title: HIST 300: Historical Method Academic Term: Spring 2006 Course Instructor: Dr. Michael J. Birkner \u2772 Hidden in Plain Sight is a collection of student papers on objects that are hidden in plain sight around the Gettysburg College campus. Topics range from the Glatfelter Hall gargoyles to the statue of Eisenhower and from historical markers to athletic accomplishments. You can download the paper in pdf format and click View Photo to see the image in greater detail.https://cupola.gettysburg.edu/hiddenpapers/1005/thumbnail.jp

Contact-allergy time

The most commonly used techniques for the in vivo evaluation of the cellular immune response include intracutaneous testing with microbial recall antigens or sensitization with neoantigens. The reliability of these tests for the individual patient usually is low due to the lack of standardization and quantification. Moreover only the efferent branch of the immune response can be judged. The dinitrochlorobenzene-contact allergy time (DNCB-CAT) is a quantitative approach for the assessment of the cellular immune response. 2% DNCBointment is applied on the upper arm in a 1 cm2 area. On the following days patch-testing with 0.05% DNCB-ointment is done on the homolateral forearm in alternating localizations till an allergic contact dermatitis reaction appears. As assessed in patients with malignant melanoma (MM, n=\\5) and with lymphoproliferative disorders (LD, η = 25), the DNCB-CAT correlates with the age of the patients and can be expressed by a formula given by the age (years) χ factor (MM = 0.16; LD = 0.17) + constant figure (MM = 5.5; LD = 4.3). There was no significant difference between the two groups or subgroups investigated. By DNCB-CAT quantitative analysis of the cellular immune response in vivo is possible. It is an appropriate model for further investigations of the cellular immunity under different clinical, histological, prognostic, and therapeutic aspects

The Role of Dialect Words in Children’s Social Decisions

Recent research suggests that young children are capable of distinguishing between phonetically dissimilar spoken accents, yet have difficulty distinguishing between phonetically similar accents (Wagner, Clopper, & Pate, 2013). The present study aimed to determine whether the presence of dialect-specific vocabulary enhances young children’s ability to categorize speakers. Participants completed four training trials in which they were familiarized with photos of two children: one of whom used American English labels for test objects and one of whom used British English labels. After training trials, participants completed eight test trials in which they were asked to infer which target child would use either British or American English labels to describe novel test objects. After all test trials were completed, participants were asked to select which target child they would prefer to ask for the name of an unfamiliar object. Participants were also asked to select which target child they would rather play a game with. Participants of all ages were significantly able to correctly categorize speakers based on whether they used dialect specific vocabulary that was familiar or unfamiliar to the participant. Participants showed a significant preference for the target child who used American dialect words. Participants also significantly trusted the American English-speaking target child over the British English-speaking target child to have the correct name for the unknown object. Neither categorization success, preference, nor selective trust differed significantly by age. These interesting results suggest that, when accent differences are too subtle for children to categorize speakers, dialect-specific vocabulary may enhance young children’s ability to categorize a speaker. The results of the preference and selective trust questions suggest that children as young as four years use their knowledge of a speaker’s vocabulary to guide their preferred social interactions, choosing to interact with others who speak similarly to them

Fast-SSC-Flip Decoding of Polar Codes

Polar codes are widely considered as one of the most exciting recent discoveries in channel coding. For short to moderate block lengths, their error-correction performance under list decoding can outperform that of other modern error-correcting codes. However, high-speed list-based decoders with moderate complexity are challenging to implement. Successive-cancellation (SC)-flip decoding was shown to be capable of a competitive error-correction performance compared to that of list decoding with a small list size, at a fraction of the complexity, but suffers from a variable execution time and a higher worst-case latency. In this work, we show how to modify the state-of-the-art high-speed SC decoding algorithm to incorporate the SC-flip ideas. The algorithmic improvements are presented as well as average execution-time results tailored to a hardware implementation. The results show that the proposed fast-SSC-flip algorithm has a decoding speed close to an order of magnitude better than the previous works while retaining a comparable error-correction performance.Comment: 5 pages, 3 figures, appeared at IEEE Wireless Commun. and Netw. Conf. (WCNC) 201

Faulty Successive Cancellation Decoding of Polar Codes for the Binary Erasure Channel

We study faulty successive cancellation decoding of polar codes for the binary erasure channel. To this end, we introduce a simple erasure-based fault model and we show that, under this model, polarization does not happen, meaning that fully reliable communication is not possible at any rate. Moreover, we provide numerical results for the frame erasure rate and bit erasure rate and we study an unequal error protection scheme that can significantly improve the performance of the faulty successive cancellation decoder with negligible overhead.Comment: As presented at ISITA 201

Faulty Successive Cancellation Decoding of Polar Codes for the Binary Erasure Channel

In this paper, faulty successive cancellation decoding of polar codes for the binary erasure channel is studied. To this end, a simple erasure-based fault model is introduced to represent errors in the decoder and it is shown that, under this model, polarization does not happen, meaning that fully reliable communication is not possible at any rate. Furthermore, a lower bound on the frame error rate of polar codes under faulty SC decoding is provided, which is then used, along with a well-known upper bound, in order to choose a blocklength that minimizes the erasure probability under faulty decoding. Finally, an unequal error protection scheme that can re-enable asymptotically erasure-free transmission at a small rate loss and by protecting only a constant fraction of the decoder is proposed. The same scheme is also shown to significantly improve the finite-length performance of the faulty successive cancellation decoder by protecting as little as 1.5% of the decoder.Comment: Accepted for publications in the IEEE Transactions on Communication

Skin thickness as a predictor of bone mineral density

Background: Low bone mineral density (BMD) has been correlated with increased risk of fracture, which in turn causes significant morbidity, mortality, and health and social care costs. Currently, bone mineral density (BMD) is measured by dual energy X-ray absorptiometry (DXA) scanning, an expensive and time consuming technique that is not universally available. An alternative method of predicting BMD is therefore required, that can be used for wider screening purposes. As the connective tissue of both skin and bone contain > 70% collagen type I, skin thickness (ST) has previously been proposed to correlate with BMD. Objective: To assess the correlation between BMD and ST; and develop a model for the prediction of BMD that includes other factors, such as age, weight, height and menopausal status, which may influence this relationship. Methods: We analysed data collected from 1406 women (mean age of 55.2 years) at the Bone Density Clinic at St. Luke's Hospital. Their BMD was measured by DXA scanning at six sites: L2, L3, and L4 vertebrae; Ward's triangle, femoral neck and trochanter at the hip. Skin thickness (ST) was measured at the T1 dermatome using ultrasonography. Medical history (including drug and bone history) was also elicited. Statistical tests, in particular multivariate analysis of variance (MANOVA), were used to select significant predictors of bone mineral density. Results: Age, weight, and skin thickness were all shown to have a significant relationship with BMD in postmenopausal women (MANOVA p= 0.001 for weight, age and p< 0.05 for skin thickness). We show a significant relationship between height and BMD at the lumbar spine (MANOVA p< 0.03) but not at the hip. Age and weight variables are of particular importance in predicting BMD in this model, while ST is more important than height. Used in conjunction, weight, age, height and skin thickness result in the model having an R2 value of 0.3 at the femoral neck, and 0.25 at L3. In non-menopausal women, we show that only weight has a significant relationship with BMD (MANOVA P< 0.007), while age, height and skin thickness do not. Conclusions: In the postmenopausal woman, a combination of weight, height, age and skin thickness allows the prediction of 30% of the BMD at the femoral neck and 25% of the BMD at L3. Measuring these variables is simple and inexpensive, and would allow large scale screening programmes for people at risk, thus reducing morbidity, mortality and costs arising from fracture.peer-reviewe

MIMO Transmission with Residual Transmit-RF Impairments

Physical transceiver implementations for multiple-input multiple-output (MIMO) wireless communication systems suffer from transmit-RF (Tx-RF) impairments. In this paper, we study the effect on channel capacity and error-rate performance of residual Tx-RF impairments that defy proper compensation. In particular, we demonstrate that such residual distortions severely degrade the performance of (near-)optimum MIMO detection algorithms. To mitigate this performance loss, we propose an efficient algorithm, which is based on an i.i.d. Gaussian model for the distortion caused by these impairments. In order to validate this model, we provide measurement results based on a 4-stream Tx-RF chain implementation for MIMO orthogonal frequency-division multiplexing (OFDM).Comment: to be presented at the International ITG Workshop on Smart Antennas - WSA 201