Patterns of Variation in the Permanent Maxillary Anterior Tooth Roots: A Different Approach to the Problem of Anterior Dental Reduction During the Transition from Archaic to Modern \u3cem\u3eHomo Sapiens\u3c/em\u3e

The following investigation centers upon an attempt to examine the problem of anterior dental reduction during the bio-cultural transition from archaic (Neandertals) to fully modern human forms. By focusing on the nature of dental root variability in the permanent maxillary anterior teeth (I1-C-), an endeavor is made to explore the absolute and relative tooth size differences characterizing the comparative samples. The samples selected for study were a collection of individual anterior teeth from an Upper Pleistocene cave deposit (Krapina, Yugoslavia) and a Plains Indian Arikara population (Larson site, South Dakota). The research objectives of this analysis are twofold: (1) To investigate the integration among the root and crown dimensions within individual anterior teeth in an effort to elucidate the differences that exist between the sample groups and generate meaningful comparisons aimed at understanding the factors contributing to the temporal patterns of dental variation; (2) To examine the relationship between the permanent maxillary anterior root dimensions (length, mesiodistal, buccolingual) and palato-facial measurements in the homogeneous population of Arikara Indians as a means of indirectly evaluating the proposition that expanded anterior dentition in Neandertals was a contributing factor toward the maintenance of vertical facial expansion and increased facial length. Absolute tooth size differences between the archaic and modern groups were found to be statistically significant for all root and crown dimensions examined. Moreover, the results of the root-crown analyses indicate that both samples demonstrate relative concordance in the degree of association between corresponding tooth diameters (mesiodistal, buccolingual), but they exhibit marked divergence concerning the correlation between root length and corresponding root and crown diameters. These differences consist of greater buccolingual expansion associated with increased root length in the Arikara and a stronger association between the mesiodistal diameter of the root and root length in the Neandertals. The divergent patterns of variation were interpreted as reflecting the effects of intense selection maintaining a tooth morphology in the Neandertals highly efficient at dissipating greater levels of occlusal stress generated during the use of the anterior teeth in non-masticatory behaviors. Based upon the results of the multivariate procedures employed to investigate the degree of integration between the anterior root dimensions and facial measurements, it is concluded that underlying effects are present which serve to associate these variables with one another. It is further concluded that expanded anterior tooth size in Neandertals was responsible for maintaining the extent of vertical facial displacement and subnasal prognathism characteristic of these archaic human groups. Finally, natural selection is considered the most likely evolutionary mechanism producing the directional pattern of variation observed in the modern comparative sample

Search For Oxygen in Cool DQ White Dwarf Atmospheres

We report new infrared spectroscopic observations of cool DQ white dwarfs by using Coolspec on the 2.7m Harlan-Smith Telescope. DQs have helium-rich atmospheres with traces of molecular carbon thought to be the result of convective dredge-up from their C/O interiors. Recent model calculations predict that oxygen should also be present in DQ atmospheres in detectable amounts. Our synthetic spectra calculations for He-rich white dwarfs with traces of C and O indicate that CO should be easily detected in the cool DQ atmospheres if present in the expected amounts. Determination of the oxygen abundance in the atmosphere will reveal the C/O ratio at the core/envelope boundary, constraining the important and uncertain ^{12}C(alpha,gamma)^{16}O reaction rate.Comment: 2 pages, 2 figures, to appear in proceedings of the 13th European Workshop on White Dwarf

Dual Fronts Propagating into an Unstable State

The interface between an unstable state and a stable state usually develops a single confined front travelling with constant velocity into the unstable state. Recently, the splitting of such an interface into {\em two} fronts propagating with {\em different} velocities was observed numerically in a magnetic system. The intermediate state is unstable and grows linearly in time. We first establish rigorously the existence of this phenomenon, called ``dual front,'' for a class of structurally unstable one-component models. Then we use this insight to explain dual fronts for a generic two-component reaction-diffusion system, and for the magnetic system.Comment: 19 pages, Postscript, A

Nickel Isotopic Composition and Nickel/Iron Ratio in the Solar Wind: Results from SOHO/CELIAS/MTOF

Using the Mass Time-of-Flight Spectrometer (MTOF)—part of the Charge, Elements, Isotope Analysis System (CELIAS)—onboard the Solar Heliospheric Observatory (SOHO) spacecraft, we derive the nickel isotopic composition for the isotopes with mass 58, 60 and 62 in the solar wind. In addition we measure the elemental abundance ratio of nickel to iron. We use data accumulated during ten years of SOHO operation to get sufficiently high counting statistics and compare periods of different solar wind velocities. We compare our values with the meteoritic ratios, which are believed to be a reliable reference for the solar system and also for the solar outer convective zone, since neither element is volatile and no isotopic fractionation is expected in meteorites. Meteoritic isotopic abundances agree with the terrestrial values and can thus be considered to be a reliable reference for the solar isotopic composition. The measurements show that the solar wind elemental Ni/Fe-ratio and the isotopic composition of solar wind nickel are consistent with the meteoritic values. This supports the concept that low-FIP elements are fed without relative fractionation into the solar wind. Our result also confirms the absence of substantial isotopic fractionation processes for medium and heavy ions acting in the solar win

Sustained expression of microRNA-155 in hematopoietic stem cells causes a myeloproliferative disorder

Mammalian microRNAs are emerging as key regulators of the development and function of the immune system. Here, we report a strong but transient induction of miR-155 in mouse bone marrow after injection of bacterial lipopolysaccharide (LPS) correlated with granulocyte/monocyte (GM) expansion. Demonstrating the sufficiency of miR-155 to drive GM expansion, enforced expression in mouse bone marrow cells caused GM proliferation in a manner reminiscent of LPS treatment. However, the miR-155–induced GM populations displayed pathological features characteristic of myeloid neoplasia. Of possible relevance to human disease, miR-155 was found to be overexpressed in the bone marrow of patients with certain subtypes of acute myeloid leukemia (AML). Furthermore, miR-155 repressed a subset of genes implicated in hematopoietic development and disease. These data implicate miR-155 as a contributor to physiological GM expansion during inflammation and to certain pathological features associated with AML, emphasizing the importance of proper miR-155 regulation in developing myeloid cells during times of inflammatory stress

Determination of Sulfur Abundance in the Solar Wind

Solar chemical abundances are determined by comparing solar photospheric spectra with synthetic ones obtained for different sets of abundances and physical conditions. Although such inferred results are reliable, they are model dependent. Therefore, one compares them with the values for the local interstellar medium (LISM). The argument is that they must be similar, but even for LISM abundance determinations models play a fundamental role (i.e., temperature fluctuations, clumpiness, photon leaks). There are still two possible comparisons—one with the meteoritic values and the second with solar wind abundances. In this work we derive a first estimation of the solar wind element ratios of sulfur relative to calcium and magnesium, two neighboring low-FIP elements, using 10 years of CELIAS/MTOF data. We compare the sulfur abundance with the abundance determined from spectroscopic observations and from solar energetic particles. Sulfur is a moderately volatile element, hence, meteoritic sulfur may be depleted relative to non-volatile elements, if compared to its original solar system valu

Dentists' knowledge and opinions of oral-systemic disease relationships: relevance to patient care and education.

Population studies consistently support associations between poor oral (periodontal) health and systemic diseases such as cardiovascular disease (CVD) and diabetes. The aim of this study was to assess the knowledge of dentists and document their opinions regarding the evidence on oral-systemic disease relationships. A survey consisting of 39 items was developed and mailed to 1,350 licensed dentists in North Carolina. After three mailings, 667 dentists (49%) meeting inclusion criteria responded. The respondents were predominantly male (76.3%), in solo practice (59.5%), and in non-rural settings (74%). More than 75% of these dentists correctly identified risk factors like diet, genetics, smoking, obesity, and physical inactivity for CVD and diabetes. The majority rated the evidence linking periodontal disease with CVD and diabetes as strong (71% and 67%, respectively). These dentists were most comfortable inquiring about patients' tobacco habits (93%), treating patients with diabetes (89%) or CVD (84%) and concurrent periodontal disease, and discussing diabetes-periodontal disease risks with patients (88%). Fewer respondents were comfortable asking patients about alcohol consumption (54%) or providing alcohol counseling (49%). Most agreed that dentists should be trained to identify risk factors (96%) or actively manage systemically diseased patients (74%). Over 90% agreed that medical and dental professionals should be taught to practice more collaboratively. These data indicate that these dentists were knowledgeable about oral-systemic health associations, had mixed comfort levels translating the evidence into clinical practice, but expressed support for interprofessional education to improve their readiness to actively participate in their patients' overall health management

Front propagation into unstable and metastable states in Smectic C* liquid crystals: linear and nonlinear marginal stability analysis

We discuss the front propagation in ferroelectric chiral smectics (SmC*) subjected to electric and magnetic fields applied parallel to smectic layers. The reversal of the electric field induces the motion of domain walls or fronts that propagate into either an unstable or a metastable state. In both regimes, the front velocity is calculated exactly. Depending on the field, the speed of a front propagating into the unstable state is given either by the so-called linear marginal stability velocity or by the nonlinear marginal stability expression. The cross-over between these two regimes can be tuned by a magnetic field. The influence of initial conditions on the velocity selection problem can also be studied in such experiments. SmC$^*$ therefore offers a unique opportunity to study different aspects of front propagation in an experimental system

New exact fronts for the nonlinear diffusion equation with quintic nonlinearities

We consider travelling wave solutions of the reaction diffusion equation with quintic nonlinearities $u_t = u_{xx} + \mu u (1 -u ) ( 1 +\alpha u + \beta u^2 +\gamma u^3)$. If the parameters $\alpha , \beta$ and $\gamma$ obey a special relation, then the criterion for the existence of a strong heteroclinic connection can be expressed in terms of two of these parameters. If an additional restriction is imposed, explicit front solutions can be obtained. The approach used can be extended to polynomials whose highest degree is odd.Comment: Revtex, 5 page