Dating the Paleolithic: Trapped charge methods and amino acid geochronology.

Despite the vast array of different geochronological tools available, dating the Paleolithic remains one of the discipline's greatest challenges. This review focuses on two different dating approaches: trapped charge and amino acid geochronology. While differing in their fundamental principles, both exploit time-dependent changes in signals found within crystals to generate a chronology for the material dated and hence, the associated deposits. Within each method, there is a diverse range of signals that can be analyzed, each covering different time ranges, applicable to different materials and suitable for different paleoenvironmental and archaeological contexts. This multiplicity of signals can at first sight appear confusing, but it is a fundamental strength of the techniques, allowing internal checks for consistency and providing more information than simply a chronology. For each technique, we present an overview of the basis for the time-dependent signals and the types of material that can be analyzed, with examples of their archaeological application, as well as their future potential.

Neanderthals on the Lower Danube: Middle Palaeolithic evidence in the Danube Gorges of the Balkans.

The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River - Tabula Traiana and Dubocka-Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state-of-the-art analytical procedures. The presentation focuses on micromorphological analyses of the caves' sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term.

Expansion of eastern Mediterranean Middle Paleolithic into the desert region in early marine isotopic stage 5.

Marine Isotopic Stage 5 is associated with wetter climatic conditions in the Saharo-Arabian deserts. This stage also corresponds to the establishment of Middle Paleolithic hominins and their associated material culture in two geographical provinces in southwest Asia-the Eastern Mediterranean woodland and the Arabian Peninsula desert. The lithic industry of the Eastern Mediterranean is characterized by the centripetal Levallois method, whereas the Nubian Levallois method characterizes the populations of the Arabian desert. The Negev Desert, situated between these regions is a key area to comprehend population movement in correlation to climatic zones. This investigation addresses the nature of the Middle Paleolithic settlement in the Negev Desert during MIS 5 by studying the site of Nahal Aqev. High resolution chronological results based on luminescence dating and cryptotephra show the site was occupied from MIS 5e to MIS 5d. The lithic industries at Nahal Aqev are dominated by centripetal Levallois core method. These data demonstrate that Nahal Aqev is much closer in its cultural attributes to the Eastern Mediterranean Middle Paleolithic than to the Arabian Desert entity. We conclude that Nahal Aqev represents an expansion of Middle Paleolithic groups from the Mediterranean woodland into the desert, triggered by better climatic conditions. These groups possibly interacted with hominin groups bearing the Nubian core tradition from the vast region of Arabia.

Room for Two: The Synaptophysin/Synaptobrevin Complex.

Synaptic vesicle release is regulated by upwards of 30 proteins at the fusion complex alone, but disruptions in any one of these components can have devastating consequences for neuronal communication. Aberrant molecular responses to calcium signaling at the pre-synaptic terminal dramatically affect vesicle trafficking, docking, fusion, and release. At the organismal level, this is reflected in disorders such as epilepsy, depression, and neurodegeneration. Among the myriad pre-synaptic proteins, perhaps the most functionally mysterious is synaptophysin (SYP). On its own, this vesicular transmembrane protein has been proposed to function as a calcium sensor, a cholesterol-binding protein, and to form ion channels across the phospholipid bilayer. The downstream effects of these functions are largely unknown. The physiological relevance of SYP is readily apparent in its interaction with synaptobrevin (VAMP2), an integral element of the neuronal SNARE complex. SNAREs, soluble NSF attachment protein receptors, comprise a family of proteins essential for vesicle fusion. The complex formed by SYP and VAMP2 is thought to be involved in both trafficking to the pre-synaptic membrane as well as regulation of SNARE complex formation. Recent structural observations specifically implicate the SYP/VAMP2 complex in anchoring the SNARE assembly at the pre-synaptic membrane prior to vesicle fusion. Thus, the SYP/VAMP2 complex appears vital to the form and function of neuronal exocytotic machinery.

On Guessing: An Alternative Adjusted Positive Learning Estimator and Comparing Probability Misspecification With Monte Carlo Simulations.

Practitioners in the sciences have used the "flow" of knowledge (post-test score minus pre-test score) to measure learning in the classroom for the past 50 years. Walstad and Wagner, and Smith and Wagner moved this practice forward by disaggregating the flow of knowledge and accounting for student guessing. These estimates are sensitive to misspecification of the probability of guessing correct. This work provides guidance to practitioners and researchers facing this problem. We introduce a transformed measure of true positive learning that under some knowable conditions performs better when students' ability to guess correctly is misspecified and converges to Hake's normalized learning gain estimator under certain conditions. We then use simulations to compare the accuracy of two estimation techniques under various violations of the assumptions of those techniques. Using recursive partitioning trees fitted to our simulation results, we provide the practitioner concrete guidance based on a set of yes/no questions.

The effects of merit-based financial aid on drinking in college.

We study the effect of state-level merit aid programs (such as Georgia's HOPE scholarship) on alcohol consumption among college students. Such programs have the potential to affect drinking through a combination of channels--such as raising students' disposable income and increasing the incentive to maintain a high GPA--that could theoretically raise or lower alcohol use. We find that the presence of a merit-aid program in one's state generally leads to an overall increase in (heavy) drinking. This effect is concentrated among men, students with lower parental education, older students, and students with high college GPA's. Our findings are robust to several alternative empirical specifications including event-study analyses by year of program adoption. Furthermore, no difference in high-school drinking is observed for students attending college in states with merit-aid programs.

Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards.

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.

Musculoskeletal manifestations of Sanfilippo Syndrome (mucopolysaccharidosis type III).

BACKGROUND: The most pronounced symptom in mucopolysaccharidosis type III (MPS III, Sanfilippo Syndrome) is the severe neurocognitive deterioration of the central nervous system. The effects of MPS III on the musculoskeletal system are less severe than those caused by other forms of MPS, however, it is our experience that many families seek orthopaedic attention for perceived musculoskeletal discomfort, particularly about the hip and spine. The purpose of this study is to report musculoskeletal findings in a case series of patients with MPS III. METHODS: This study represents a retrospective case series of all records available from 2 institutions on patients with MPS III. Chart and radiographic review was performed and outcomes tabulated. Our hypotheses are: (1) Musculoskeletal abnormalities are prevalent in children with MPS III and (2) Musculoskeletal deformities in children with MPS III may require surgical intervention. RESULTS: Eighteen patients were identified (10 female and 8 male) with an average age of 10.3 years. Three had significant scoliosis (21 to 99 degrees) and 2 others had L1 hypoplasia. Four patients had osteonecrosis of the femoral heads. One patient required a carpal tunnel release, and another a trigger thumb release. There were no cases of cervical instability. CONCLUSIONS: In our study with these patients, we have observed several unreported musculoskeletal manifestations of MPS III. Osteonecrosis of the hips can be a source of severe discomfort for these children. Although uncommon, operative intervention for orthopaedic conditions is sometimes warranted. Operative indications in this cohort include progressive scoliosis of large magnitude, carpal tunnel syndrome, and trigger digits. LEVEL OF EVIDENCE: Level IV; case series.