Teaching Human Evolution

As science educators, we have two goals in writing this paper. The first is to show the importance of teaching human evolution to all students. The second is to provide up-to-date resources for classroom teachers to use in teaching the subject. Secondary biology textbooks suffer from the inherent limitations of mass produced books making it difficult for them to stay current with rapidly changing scientific fields such as paleoanthropology. One of our motives for writing this paper is to compensate for this inherent limitation of textbooks. The most important resource we provide is a review of current scientific research on human evolution that stresses the broad framework of what is reliably known about our origins. To this we have included a list of recommended books taken from our research that we feel are the most useful and accessible. In addition to text resources, we have added a list of web sites on human evolution that provide an increasingly sophisticated source of information. Together, this material should provide teachers with a variety of up-to-date resources for teaching human evolution

Synthesis of Observations from the Precision Atmosphere Marine Boundary Layer Experiment (PreAMBLE)

Research flights during the Precision Atmospheric Marine Boundary Layer Experiment (PreAMBLE) in Southern California during May–June 2012 focused on three main features found in the nearshore marine boundary layer (MBL): the coastal jet (10 flights), the Catalina eddy (3 flights), and the initiation of a southerly surge (1 flight). Several topics were examined with case studies, but results from individual events may not represent typical conditions. Although these flights do not constitute a long-term set of data, observations from PreAMBLE are used to find common features. Two main topics are addressed: the MBL collapse into the expansion fan, and the subsequent transition into the Santa Barbara Channel (SBC). The midmorning to late afternoon flights occur during moderate to strong northerly wind. Slope of the MBL in the expansion fan varies and wave perturbations can be embedded within the expansion fan. As the cool MBL flow turns into the SBC, it moves underneath a deeper and warmer MBL that originates from the southeast over the warmer ocean. The temperature inversion between the cool and warm MBL erodes toward the east until there is only the inversion between the warm MBL and free troposphere. The dissipation of the lower layer into the SBC observed by the aircraft differs from previous conceptual models that depict a continuous MBL that thins and then deepens again in the SBC, which was inferred from sparse observations and numerical simulations. Only one flight within the SBC detected a hydraulic jump from 100 to 200 m above the surface

Airborne Observations of a Catalina Eddy

This is the publisher's version, also available electronically from http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-13-00029.1Summertime low-level winds over the ocean adjacent to the California coast are typically from the north, roughly parallel to the coastline. Past Point Conception the flow often turns eastward, thereby generating cyclonic vorticity in the California Bight. Clouds are frequently present when the cyclonic motion is well developed and at such times the circulation is referred to as a Catalina eddy. Onshore flow south of the California Bight associated with the eddy circulation can result in a thickening of the low-level marine stratus adjacent to the coast. During nighttime hours the marine stratus typically expands over a larger area and moves northward along the coast with the cyclonic circulation. A Catalina eddy was captured during the Precision Atmospheric Marine Boundary Layer Experiment in June of 2012. Measurements were made of the cloud structure in the marine layer and the horizontal pressure field associated with the cyclonic circulation using the University of Wyoming King Air research aircraft. Airborne measurements show that the coastal mountains to the south of Los Angeles block the flow, resulting in enhanced marine stratus heights and a local pressure maximum near the coast. The horizontal pressure field also supports a south–north movement of marine stratus. Little evidence of leeside troughing south of Santa Barbara, California, was observed for this case, implying that the horizontal pressure field is forced primarily through topographic blocking by the coastal terrain south of Los Angeles, California, and the ambient large-scale circulation associated with the mean flow

Aircraft Measurements and Numerical Simulations of an Expansion Fan off the California Coast

Mountains along the California coastline play a critical role in the dynamics of marine atmospheric boundary layer (MBL) airflow in the vicinity of the shoreline. Large changes in the MBL topology have been known to occur downwind of points and capes along the western coast of the United States. Large spatial gradients in wind and temperature become established that can cause anomalous electromagnetic wave propagation. Detailed airborne measurements using the University of Wyoming King Air were conducted to study the adjustment of the MBL to the Point Arguello and Point Conception headlands. Pronounced thinning of the MBL consistent with an expansion fan occurred to the south of Point Conception on 13 June 2012. A sharp cloud edge was collocated with the near collapse of the MBL. D-value cross sections derived from differential GPS altitude measurements allow assessment of the vertical profile of the horizontal pressure gradient force and hence thermal wind forcing in response to the near collapse of the MBL. The Weather Research and Forecasting Model was run with a 1-km grid spacing to examine the atmospheric adjustment around Point Conception during this period. Results from the simulations including the vertical cross sections of the horizontal pressure gradient force were consistent with the aircraft observations. Model results suggest that divergence occurs as the flow rounds Point Conception, characteristic of an expansion fan. Wind speeds in the MBL increase coincident with the decrease in MBL thickness, and subsiding flow associated with the near collapse of the MBL is responsible for the sharp cloud edge

Airborne Measurements of Coastal Jet Transition around Point Conception, California

This is the publisher's version, also available electronically from http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-13-00030.1Low-level winds along the Californian coast during spring and early summer are typically strong and contained within the cool, well-mixed marine boundary layer (MBL). A temperature inversion separates the MBL from the warmer free troposphere. This setup is often represented by a two-layer shallow-water system with a lateral boundary. Near a prominent point such as Point Conception, California, the fast-moving MBL flow is supercritical and can exhibit distinct features including a compression bulge and an expansion fan. Measurements from the University of Wyoming King Air research aircraft on 19 May 2012 during the Precision Atmospheric MBL Experiment (PreAMBLE) captured wind in excess of 14 m s−1 off of Point Conception under clear skies and wind ~2 m s−1 east of San Miguel in the California Bight. A compression bulge was identified upwind of Point Conception. When the flow rounds the point, the MBL undergoes a near collapse and there is a spike in MBL height embedded in the general decrease of MBL height with greater turbulence just downwind that is associated with greater mixing through the inversion layer. Lidar and in situ measurements reveal that transport of continental aerosol is present near the pronounced MBL height change and that there is a complex vertical structure within the Santa Barbara Channel. Horizontal pressure gradients are obtained by measuring the slope of an isobaric surface. Observations of wind and pressure perturbations are able to be linked through a simple Bernoulli relationship. Variation of MBL depth explains most, but not all of the variation of the isobaric surface

Coastal Jet Adjustment near Point Conception, California, with Opposing Wind in the Bight

This is the publisher's version, also available electronically from http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-13-00177.1Typical spring and summer conditions offshore of California consist of strong northerly low-level wind contained within the cool, well-mixed marine boundary layer (MBL) that is separated from the warm and dry free troposphere by a sharp temperature inversion. This system is often represented by two layers constrained by a lateral boundary. Aircraft measurements near Point Conception, California, on 3 June 2012 during the Precision Atmospheric MBL Experiment (PreAMBLE) captured small-scale features associated with northerly flow approaching the point with the added complexity of encountering opposing wind in the Santa Barbara Channel. An extremely sharp cloud edge extends south-southwest of Point Conception and the flight strategy consisted of a spoke pattern to map the features across the cloud edge. Lidar and in situ measurements reveal a nearly vertical jump in the MBL from 500 to 100 m close to the coast and a sharp edge at least 70 km away from the coast. In this case, it is hypothesized that it is not solely hydraulic features responsible for the jump, but the opposing flow in the Santa Barbara Channel is a major factor modifying the flow. Just southeast of Point Conception are three distinct layers: a shallow, cold layer near the surface with northwesterly winds associated with an abrupt decrease in MBL height from the north that thins eastward into the Santa Barbara Channel; a cool middle layer with easterly wind whose top slopes upward to the east; and the warm and dry free troposphere above

Research Aircraft Determination of D-Value Cross Sections

This is the published version.Use of an airborne platformto determine the dynamics of atmosphericmotion has been ongoing for over three decades. Much of the effort has been centered on the determination of the horizontal pressure gradient force along an isobaric surface, and with wind measurements the nongeostrophic components of motion can be obtained. Recent advances using differential GPS-based altitude measurements allow accurate assessment of the geostrophic wind. Porpoise or saw tooth maneuvers are used to determine the vertical cross section of the horizontal pressure gradient force. D-values, the difference of the height of a given pressure level from that in a reference atmosphere, are used to isolate the vertical structure of the horizontal component of the pressure gradient force from the vastly larger hydrostatic pressure gradient. Comparison of measured D-value cross sections with airborne measurements of the horizontal pressure gradient is shown. Comparison of D-values with output from the WRF Model demonstrates that the airborne measurements are consistent with fine scale numerical simulations. This technique provides a means of inferring the thermal wind, thereby enabling a detailed examination of the vertical structure of the forcing of mesoscale and synoptic-scale wind regimes

Aircraft Observations of a Coastally Trapped Wind Reversal off the California Coast

This is the publisher's version, also available electronically from http://journals.ametsoc.org/doi/abs/10.1175/2007MWR2199.1.The summertime marine atmospheric boundary layer off the California coast is normally characterized by northerly winds associated with the Pacific high. This pattern is occasionally disturbed by episodes of southerly winds and a finger of fog or low stratus adjacent to the coastline extending approximately 100 km offshore. These events propagate northward along the coast with speeds between 5 and 12 m s−1 and have a life span of several days. These occurrences have been referred to as coastally trapped wind reversals (CTWRs), coastally trapped disturbances, or southerly surges. The CTWR event of 22–25 June 2006 was explored by the University of Wyoming King Air research aircraft to document the physical characteristics of the wind reversal in an attempt to infer the forcing mechanisms responsible for the propagation. Two flights from 23 June are presented that are representative of the CTWR during its mature stage. Sawtooth maneuvers depict the CTWR vertical structure, and isobaric legs directly measure the horizontal pressure gradient force (PGF). Observations showed a thickening of the CTWR layer in an alongshore direction to the south. The inversion layer varies throughout the day with the final sawtooth leg depicting clear dynamic destabilization within the inversion layer. A PGF is present at the head of the CTWR that is directed northward. No significant PGF was detected in the cross-shore direction, suggesting that for this case there is little variation in the depth of the marine boundary layer normal to the coast

Study of Stopping Sites of B12 Nuclei Implanted in Hexagonal Single-Crystals

A series of experiments to study the stopping sites of 12B nuclei implanted in single crystals of Be and Mg will be discussed. Previous measurements of the quadrupole couplings of 12B in these metals indicated that two different stopping sites existed, one of which produced a negligible quadrupole coupling

Quadrupole Couplings of N12 and B12 Implanted in Metal Single-Crystals

Measurements have been made of the quadrupole couplings of 12N implanted in single crystals of Be and Mg and of 12B implanted in a single crystal of Zn. A comparison of the 12N couplings in Be and Mg suggests that (i) the final stopping sites of the implanted 12N ions are substitutional sites, i.e., the 12N ions occupy metal-ion lattice positions, and (ii) the 12N ions implanted in Be and Mg have the same charge state and quadrupole shielding factor. A procedure is outlined for deducing Q(12N). The 12B couplings in Zn imply the existence of two inequivalent stopping sites. The problems encountered in deducing Q(12B) from couplings in metal hexagonal crystals are discussed