Breastfeeding and the Risk of Childhood Obesity

Breastfeeding is suggested to be a potential obesity prevention strategy, but the evidence that breast-fed infants have a lower risk of later obesity is equivocal. Fourteen studies published between 2003 and 2006 that considered the relationship between breastfeeding and risk of childhood overweight and obesity were reviewed. Three studies reported a protective effect in children (i.e., increased duration of breastfeeding was associated with a lower risk of childhood overweight/ obesity), 4 reported a partial protective effect (i.e., only evident in a subgroup), 6 reported no protective effect, and 1 reported a protective effect in children but not in adults. While there is some evidence that breastfeedingmay help to prevent childhood obesity, it should not be viewed as the only preventative nutrition measure. In the U.S., rates of breastfeeding have risen while rates for childhood obesity have increased dramatically. This finding reinforces the view that many factors are involved in maintaining a healthy body weight

Estimates of body sizes at maturation and at sex change, and the spawning seasonality and sex ratio of the endemic Hawaiian grouper (Hyporthodus quernus, F. Epinephelidae)

A case study of the reproductive biology of the endemic Hawaiian grouper or hapu’upu’u (Hyporthodus quernus) is presented as a model for comprehensive future studies of economically important epinephelid groupers. Specimens were collected throughout multiple years (1978–81, 1992–93, and 2005–08) from most reefs and banks of the Northwestern Hawaiian Islands. The absence of small males, presence of atretic oocytes and brown bodies in testes of mature males, and both developed ovarian and testicular tissues in the gonads of five transitional fish provided evidence of protogynous hermaphroditism. No small mature males were collected, indicating that Hawaiian grouper are monandrous (all males are sex-changed females). Complementary microscopic criteria also were used to assign reproductive stage and estimate median body sizes (L50) at female sexual maturity and at adult sex change from female to male. The L50 at maturation and at sex change was 580 ±8 (95% confidence interval [CI]) mm total length (TL) and 895 ±20 mm TL, respectively. The adult sex ratio was strongly female biased (6:1). Spawning seasonality was described by using gonadosomatic indices. Females began ripening in the fall and remained ripe through April. A February–June main spawning period that followed peak ripening was deduced from the proportion of females whose ovaries contained hydrated oocytes, postovulatory follicles, or both. Testes weights were not affected by season; average testes weight was only about 0.2% of body weight—an order of magnitude smaller than that for ovaries that peaked at 1–3% of body weight. The species’ reproductive life history is discussed in relation to its management

Wear striation direction on primate teeth: A scanning electron microscope examination

Two experimental methods were used to produce wear stria-tions in one direction on unworn teeth. These include: (1) sliding 22 American Indian (Juntunen site, Michigan; Late Woodland) newly erupted incisors, by hand, across a flat glass surface covered with fine loose sand; and (2) using a unidirectional motor driven mechanical wear machine to draw 56 modern human dental extractions across a flat glass surface covered with silicon carbide powder of different grit sizes. A scanning electron microscope examination of individual wear striation morphology indicates that these wear striations begin with broad pits and have extending grooves that become narrower; characteristics that indicate the motion of wear. Patterns of wear striations on the worn dentitions of American Indians (Juntunen site) and the paleocene primate Phenacolemur pagei show similar characteristics and correspond to the buccal phase of mastication when the mandible is drawn upward, forward and slightly medially into centric occlusion. The data provided by this study can be used to test competing hypotheses concerning the direction of mandibular movement during mastication and food preparation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37589/1/1330500204_ftp.pd

Anterior dental microwear and its relationship to diet and feeding behavior in three african primates ( Pan troglodytes troglodytes, Gorilla gorilla gorilla and Papio hamadryas )

Anterior dental microwear is shown to be related to diet and to feeding habits in three groups of extant African primates including Pan troglodytes troglodytes, Gorilla gorilla gorilla and Papio hamadryas . Five distinct types of incisal microwear are found in these groups. These include: fine wear striae, polish, small pits, large pits and microflakes. It is demonstrated that each species exhibits a different set of microwear types. Chimpanzees exhibit extensive pitting, mesiodistally oriented fine wear striae and small areas of polish, features of microwear that are probably related to the husking of hard fruit skins and the occasional stripping of leaves. Gorillas show large areas of polish, small pits and labiolingually oriented wear striae, a combination of features that may be associated with the stripping of leaves and pith. Baboons show extensive edge damage involving clusters of large pits and microflakes; this set of microwear types may be related to the initial chewing of gravel-laden seeds, roots and rhizomes. Microwear found on the canine/premolar complex of all three groups corresponds to the puncture-crushing and to the slicing of food.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41600/1/10329_2006_Article_BF02381245.pd

The essentiality of arachidonic acid in infant development

Arachidonic acid (ARA, 20:4n-6) is an n-6 polyunsaturated 20-carbon fatty acid formed by the biosynthesis from linoleic acid (LA, 18:2n-6). This review considers the essential role that ARA plays in infant development. ARA is always present in human milk at a relatively fixed level and is accumulated in tissues throughout the body where it serves several important functions. Without the provision of preformed ARA in human milk or infant formula the growing infant cannot maintain ARA levels from synthetic pathways alone that are sufficient to meet metabolic demand. During late infancy and early childhood the amount of dietary ARA provided by solid foods is low. ARA serves as a precursor to leukotrienes, prostaglandins, and thromboxanes, collectively known as eicosanoids which are important for immunity and immune response. There is strong evidence based on animal and human studies that ARA is critical for infant growth, brain development, and health. These studies also demonstrate the importance of balancing the amounts of ARA and DHA as too much DHA may suppress the benefits provided by ARA. Both ARA and DHA have been added to infant formulas and follow-on formulas for more than two decades. The amounts and ratios of ARA and DHA needed in infant formula are discussed based on an in depth review of the available scientific evidence

The B_s and D_s decay constants in 3 flavor lattice QCD

Capitalizing on recent advances in lattice QCD, we present a calculation of the leptonic decay constants f_{B_s} and f_{D_s} that includes effects of one strange sea quark and two light sea quarks. The discretization errors of improved staggered fermion actions are small enough to simulate with 3 dynamical flavors on lattices with spacings around 0.1 fm using present computer resources. By shedding the quenched approximation and the associated lattice scale ambiguity, lattice QCD greatly increases its predictive power. NRQCD is used to simulate heavy quarks with masses between 1.5 m_c and m_b. We arrive at the following results: f_{B_s} = 260 \pm 7 \pm 26 \pm 8 \pm 5 MeV and f_{D_s} = 290 \pm 20 \pm 29 \pm 29 \pm 6 MeV. The first quoted error is the statistical uncertainty, and the rest estimate the sizes of higher order terms neglected in this calculation. All of these uncertainties are systematically improvable by including another order in the weak coupling expansion, the nonrelativistic expansion, or the Symanzik improvement program.Comment: 4 page

Toward a Millimeter-Scale Tendon-Driven Continuum Wrist with Integrated Gripper for Microsurgical Applications

Microsurgery is a particularly impactful yet challenging form of surgery. Robot assisted microsurgery has the potential to improve surgical dexterity and enable precise operation on such small scales in ways not previously possible. Intraocular microsurgery is a particularly challenging domain in part due to the lack of dexterity that is achievable with rigid instruments inserted through the eye. In this work, we present a new design for a millimeter-scale, dexterous wrist intended for microsurgery applications. The wrist is created via a state-of-the-art two-photon-polymerization (2PP) microfabrication technique, enabling the wrist to be constructed of flexible material with complex internal geometries and critical features at the micron-scale. The wrist features a square cross section with side length of 1.25 mm and total length of 3.75 mm. The wrist has three tendons routed down its length which, when actuated by small-scale linear actuators, enable bending in any plane. We present an integrated gripper actuated by a fourth tendon routed down the center of the robot. We evaluate the wrist and gripper by characterizing its bend-angle. We achieve more than 90 degrees bending in both axes. We demonstrate out of plane bending as well as the robot's ability to grip while actuated. Our integrated gripper/tendon-driven continuum robot design and meso-scale assembly techniques have the potential to enable small-scale wrists with more dexterity than has been previously demonstrated. Such a wrist could improve surgeon capabilities during teleoperation with the potential to improve patient outcomes in a variety of surgical applications, including intraocular surgery.Comment: 2 pages, 3 figures, submitted to the 2023 Hamlyn Symposium on Medical Robotics conferenc

Dental and cranial variation in living Indriidae

Four species of Indriidae are extant in Madagascar. We have studied large samples of each of these to characterize dental and cranial variation, and to estimate the degree of sexual dimorphism in the dentition and cranium. Two dental fields are apparent, characterized by reduced variability: (1) a canine field centered on the upper canine and occluding caniniform lower premolar, and (2) a cheek tooth field centered on the second molars. No consistent pattern of sexual dimorphism was found in dental or cranial dimensions, and we conclude that none of the four species is sexually dimorphic. This lack of dental and cranial dimorphism is unusual in primates, and probably reflects the relatively limited aggressive behavior and the lack of male dominance in Indriidae.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41599/1/10329_2006_Article_BF02373833.pd