Laser Ablation - Accelerator Mass Spectrometry: An Approach for Rapid Radiocarbon Analyses of Carbonate Archives at High Spatial Resolution.

A new instrumental setup, combining laser ablation (LA) with accelerator mass spectrometry (AMS), has been investigated for the online radiocarbon ((14)C) analysis of carbonate records. Samples were placed in an in-house designed LA-cell, and CO2 gas was produced by ablation using a 193 nm ArF excimer laser. The (14)C/(12)C abundance ratio of the gas was then analyzed by gas ion source AMS. This configuration allows flexible and time-resolved acquisition of (14)C profiles in contrast to conventional measurements, where only the bulk composition of discrete samples can be obtained. Three different measurement modes, i.e. discrete layer analysis, survey scans, and precision scans, were investigated and compared using a stalagmite sample and, subsequently, applied to terrestrial and marine carbonates. Depending on the measurement mode, a precision of typically 1-5% combined with a spatial resolution of 100 µm can be obtained. Prominent (14)C features, such as the atomic bomb (14)C peak, can be resolved by scanning several cm of a sample within 1 h. Stalagmite, deep-sea coral, and mollusk shell samples yielded comparable signal intensities, which again were comparable to those of conventional gas measurements. The novel LA-AMS setup allowed rapid scans on a variety of sample materials with high spatial resolution.

Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes.

Some of the most basic questions of sea turtle life history are also the most elusive. Many uncertainties surround lifespan, growth rates, maturity and spatial structure, yet these are critical factors in assessing population status. Here we examine the keratinized hard tissues of the hawksbill (Eretmochelys imbricata) carapace and use bomb radiocarbon dating to estimate growth and maturity. Scutes have an established dietary record, yet the large keratin deposits of hawksbills evoke a reliable chronology. We sectioned, polished and imaged posterior marginal scutes from 36 individual hawksbills representing all life stages, several Pacific populations and spanning eight decades. We counted the apparent growth lines, microsampled along growth contours and calibrated Δ(14)C values to reference coral series. We fit von Bertalanffy growth function (VBGF) models to the results, producing a range of age estimates for each turtle. We find Hawaii hawksbills deposit eight growth lines annually (range 5-14), with model ensembles producing a somatic growth parameter (k) of 0.13 (range 0.1-0.2) and first breeding at 29 years (range 23-36). Recent bomb radiocarbon values also suggest declining trophic status. Together, our results may reflect long-term changes in the benthic community structure of Hawaii reefs, and possibly shed light on the critical population status for Hawaii hawksbills.

Identification of a major GpVI-binding locus in human type III collagen.

We have analyzed the adhesion of human and murine platelets, and of recombinant human and murine GpVI ectodomains, to synthetic triple-helical collagen-like peptides. These included 57 peptides derived from the sequence of human type III collagen and 9 peptides derived from the cyanogen bromide fragment of bovine type III collagen, alpha1(III)CB4. We have identified several peptides that interact with GpVI, in particular a peptide designated III-30 with the sequence GAOGLRGGAGPOGPEGGKGAAGPOGPO. Both human and murine platelets bound to peptide III-30 in a GpVI-dependent manner. III-30 also supported binding of recombinant GpVI ectodomains. Cross-linked III-30 induced aggregation of human and murine platelets, although with a lower potency than collagen-related peptide. Modifications of the peptide sequence indicated that the hydroxyproline residues play a significant role in supporting its GpVI reactivity. However, many peptides containing OGP/GPO motifs did not support adhesion to GpVI. These data indicate that the ability of a triple-helical peptide to bind GpVI is not solely determined by the presence or spatial arrangement of these OGP/GPO motifs within the peptides.

Psychosocial health in displaced Iraqi care-seekers in non-governmental organization clinics in Amman, Jordan: an unmet need.

INTRODUCTION: Populations displaced by conflict face numerous threats to their psychological well-being; consequently, the prevalence of mental health problems, including anxiety, depression, and post-traumatic stress disorder can be elevated as compared to populations who have not experienced forced displacement. PROBLEM: Little is known about the mental health needs of displaced Iraqis. The factors associated with a need for psychological services among patients at seven clinics served by two NGOs that are known sources of care for the displaced Iraqi population in Amman, Jordan were explored. METHODS: The survey was conducted in January and February 2008 and included a random sample of care seekers from seven clinics selected using interval sampling. Interviews on the health needs of displaced Iraqis and their access to services, including mental health services lasting approximately 20 minutes were conducted. RESULTS: Of the 664 survey participants, 49% (95% CI = 45-53%) of respondents reported needing mental health services and 5% (95% CI = 3-8%) of those in need had access to services. The length of time spent in Jordan (adjusted OR = 1.08; 95% CI = 1.00-1.11) was associated with the need for mental health services and the adjusted odds of requiring psychological services was 39% less for individuals from outside of Baghdad as compared to Baghdad residents (OR = 0.61; 95% CI = 0.38-0.98). Responders citing violence as a factor were twice as likely to be from Baghdad (OR = 2.28; 95% CI = 1.03-6.91), while interviewees reporting displacement as a cause for needing mental health services were twice as likely to be female (OR = 2.14; 95% CI = 1.12-4.18). In individuals 35-44 years of age (OR = 0.36; 95% CI = 0.14-0.87) the need for mental health services due to displacement decreased by 64%, while being a part of a female-headed household decreased the need by 81% (OR = 0.19; 95% CI = 0.06-0.57%). CONCLUSIONS: More attention should be given to expanding the local Jordanian health system capacity for the provision of mental service. Targeted social and psychiatric interventions that are culturally sensitive and aligned with Inter-Agency Standing Committee recommendations should be developed to compliment and expand the existing mental health service capacity in Jordan.

Reconstructing reef fish communities using fish otoliths in coral reef sediments.

Little is known about long-term changes in coral reef fish communities. Here we present a new technique that leverages fish otoliths in reef sediments to reconstruct coral reef fish communities. We found over 5,400 otoliths in 169 modern and mid-Holocene bulk samples from Caribbean Panama and Dominican Republic mid-Holocene and modern reefs, demonstrating otoliths are abundant in reef sediments. With a specially-built reference collection, we were able to assign over 4,400 otoliths to one of 56 taxa (35 families) though mostly at genus and family level. Many otoliths were from juvenile fishes for which identification is challenging. Richness (by rarefaction) of otolith assemblages was slightly higher in modern than mid-Holocene reefs, but further analyses are required to elucidate the underlying causes. We compared the living fish communities, sampled using icthyocide, with the sediment otolith assemblages on four reefs finding the otolith assemblages faithfully capture the general composition of the living fish communities. Radiocarbon dating performed directly on the otoliths suggests that relatively little mixing of sediment layers particularly on actively accreting branching coral reefs. All otolith assemblages were strongly dominated by small, fast-turnover fish taxa and juvenile individuals, and our exploration on taxonomy, functional ecology and taphonomy lead us to the conclusion that intense predation is likely the most important process for otolith accumulation in reef sediments. We conclude that otolith assemblages in modern and fossil reef sediments can provide a powerful tool to explore ecological changes in reef fish communities over time and space.

Bigmouth Buffalo Ictiobus cyprinellus sets freshwater teleost record as improved age analysis reveals centenarian longevity.

Understanding the age structure and population dynamics of harvested species is crucial for sustainability, especially in fisheries. The Bigmouth Buffalo (Ictiobus cyprinellus) is a fish endemic to the Mississippi and Hudson Bay drainages. A valued food-fish for centuries, they are now a prized sportfish as night bowfishing has become a million-dollar industry in the past decade. All harvest is virtually unregulated and unstudied, and Bigmouth Buffalo are declining while little is known about their biology. Using thin-sectioned otoliths and bomb-radiocarbon dating, we find Bigmouth Buffalo can reach 112 years of age, more than quadrupling previous longevity estimates, making this the oldest known freshwater teleost (~12,000 species). We document numerous populations that are comprised largely (85-90%) of individuals over 80 years old, suggesting long-term recruitment failure since dam construction in the 1930s. Our findings indicate Bigmouth Buffalo require urgent attention, while other understudied fishes may be threatened by similar ecological neglect.

Proximal row carpectomy.

Proximal row carpectomy is extremely useful as a wrist reconstructive technique for cases of degenerative joint arthritis of the radiocarpal joint cause by scapholunate advanced collapse, scapholunate advanced collapse, schaphoid nonunion advanced collapse, trans-scaphoid perilunate fracture dislocations, lunate dislocations, and Kienböck disease. It should be selected with caution for patients younger than 35 years old. The procedure can be performed with or without temporary internal fixation with with Kirschner wires, and adjunctive techniques of dorsal capsule interposition, proximal capitate excision, and radial styloidectomy can be used. The longevity of the operation is good, but the patient should be informed preoperatively that secondary procedures may be required. Based on historical series, these procedures have included addition have included of radial styloidectomy when this has not been performed at the index procedure, revision of the surgery with capitate debridement or conversion to total wrist arthodesis. Conversion of proximal row carpectomy to total wrist arthoplasty with implants can be contemplated in selected patient particularly as newer implants are designed. The technique the senior author has used on occasion has been to perform revision surgery on those patients who have chronic pain who might need further debridement of the radius in the radial styloid, the proximal capitate, or evaluation of the integrity of the interposition.

Videotaped patient stories: impact on medical students' attitudes regarding healthcare for the uninsured and underinsured.

The attitudes of medical students toward the current United States healthcare system are not well described in the literature. A graded survey was developed to assess awareness and motivation toward the care of the uninsured and underinsured as well as the impact of a video intervention on these attitudes. The survey, which showed good internal consistency (Cronbach's alpha = 0.85), was administered before and after viewing a collection of videotaped patient stories. Although a spectrum of beliefs emerged from the analysis of survey responses, some common attitudes were identified. Eighty-five percent of respondents either agreed or strongly agreed that medical care should be provided to everyone, regardless of their ability to pay. In addition, 66% indicated they would be willing to forgo a portion of their income to provide care to those who do not have access to healthcare services. These values were strongly correlated with increasing respondent age and primary care specialty choice (p<0.01). The video intervention did not heavily influence student responses, perhaps due to a ceiling effect created by the large number of students who were already sympathetic toward the underserved. Overall, this data reflects that United States medical students recognize a need to provide care to the underserved and are willing to make personal sacrifices to meet that need.

Healthcare reform and the next generation: United States medical student attitudes toward the Patient Protection and Affordable Care Act.

CONTEXT: Over one year after passage of the Patient Protection and Affordable Care Act (PPACA), legislators, healthcare experts, physicians, and the general public continue to debate the implications of the law and its repeal. The PPACA will have a significant impact on future physicians, yet medical student perspectives on the legislation have not been well documented. OBJECTIVE: To evaluate medical students' understanding of and attitudes toward healthcare reform and the PPACA including issues of quality, access and cost. DESIGN, SETTING, AND PARTICIPANTS: An anonymous electronic survey was sent to medical students at 10 medical schools (total of 6982 students) between October-December 2010, with 1232 students responding and a response rate of 18%. MAIN OUTCOME MEASURES: Medical students' views and attitudes regarding the PPACA and related topics, measured with Likert scale and open response items. RESULTS: Of medical students surveyed, 94.8% agreed that the existing United States healthcare system needs to be reformed, 31.4% believed the PPACA will improve healthcare quality, while 20.9% disagreed and almost half (47.7%) were unsure if quality will be improved. Two thirds (67.6%) believed that the PPACA will increase access, 6.5% disagreed and the remaining 25.9% were unsure. With regard to containing healthcare costs, 45.4% of participants indicated that they are unsure if the provisions of the PPACA will do so. Overall, 80.1% of respondents indicated that they support the PPACA, and 78.3% also indicated that they did not feel that reform efforts had gone far enough. A majority of respondents (58.8%) opposed repeal of the PPACA, while 15.0% supported repeal, and 26.1% were undecided. CONCLUSION: The overwhelming majority of medical students recognized healthcare reform is needed and expressed support for the PPACA but echoed concerns about whether it will address issues of quality or cost containment.