Distortion of Globular Clusters by Galactic Bulges

One of the external fields that influences the population of globular clusters is that due to galactic bulges. In extreme situations, perigalactic distances $r_p \le 100$ pc, globular clusters could suffer total disruption in a single passage. A more common scenario is that for cluster orbits with $r_p \ge 200$ pc. We investigate the effects of tidal forces from a bulge on the shape of globular clusters for this type of encounters. We find distortions characterized by ``twisting isophotes'' and consider the potential for observability of this effect. In the Milky Way, a typical globular cluster must pass within several hundred pc of the center to experience substantial distortion, and it is possible that this has happened recently to one or two present day clusters. We estimate that this distortion could be observed even for globulars in dense fields toward the bulge. In more extreme environments such as giant ellipticals or merger products with newly formed globulars, this effect could be more common, extending out to orbits that pass within 1 kpc of the bulge center. This would lead to a substantial shift in the eccentricity distribution of globulars in those galaxies.Comment: 12 pages, 8 figure

Arm Flexion, Arm Extension, and Motivational Responses to Feared Stimuli

People are highly motivated to approach attractive stimuli and to avoid noxious stimuli (e.g., Lang, Bradley, & Cuthbert, 1990; Schneirla, 1959. Approach of attractive stimuli (e.g., obtaining food, pursuit of sexual relations) and avoidance of noxious stimuli (e.g., defense against predatory threat) ensure continued survival, a basic goal of all living organisms. And yet, sometimes approach/avoidance behavior is maladaptive. For instance, individuals with intense fears of spiders experience strong avoidance motivation in spite of the relative harmlessness of most spiders. The research reported here evaluated whether a simple, easily executed bodily manipulation can dampen the strong avoidance motivation that typically results when a person is exposed to cues of a feared stimulus (e.g., Hamm, Cuthbert, Globisch, & Vaitl, 1997). Previous research in our laboratory (Thibodeau, 2011) and others (e.g., Cacioppo, Priester, & Berntson, 1993) suggests that the execution of simple actions normally associated with approach behavior (e.g., arm flexion, as when pulling attractive objects near) is sufficient, by itself, to elicit approach motivation. The current research explored whether spider- and snake-fearful undergraduates and non-fearful controls who were exposed to photographs of fear-relevant stimuli could diminish the size and strength of avoidance motives simply by concurrently engaging in an approach-related action. The startle probe (Lang et al., 1990) was used to index the strength of participants’ avoidance motives. METHOD Forty undergraduates participated in the study for course credit. Fearful participants (n = 24) obtained scores above 20 on self-report questionnaires measuring snake or spider fear (Klorman, Weerts, Hastings, Melamed, & Lang, 1974); controls (n = 16) obtained scores below 6. The startle reflex was indexed by electromyographic (EMG) recording of the orbicularis oculi (“blink”) muscle, contraction of which causes the sudden closure of the eyelids that represents a key element of the startle response. Participants viewed a series of 45 pictures (15 spiders or snakes, 15 household objects, 15 fixation crosses) and concurrently performed arm flexion (an approach action), arm extension (an avoidance action), or squeezed the edge of a table (a neutral control action); all pictures and actions were presented in a quasi-randomized sequence. Bursts of 50-ms white noise (98 dB) were unpredictably presented to elicit the startle reflex. We followed standard procedures for the reduction and scoring of startle data (Blumenthal et al., 2005). RESULTS AND DISCUSSION Contrary to predictions, the motivational actions were not related to the size of the startle reflex (Action main effect; p = .27). This pattern held for both groups (Action x Group interaction; p = .17), and it was not moderated by Picture Type (Action x Picture Type interaction; p = .90). The three-way interaction was also nonsignificant (p = .15). Importantly, however, a significant main effect of Picture Type (F[2,76] = 7.03, p = .002) confirmed a previously documented pattern of heightened startle reactivity during viewing of fear-relevant pictures (e.g., Hamm et al., 1997). Overall, the present data suggest that the motivational actions utilized here (Cacioppo et al., 1993; Thibodeau, 2011) are insufficient to moderate avoidance-related emotional responses to feared stimuli

Southwestern Minnesota Farm Business Management Association 2008 Annual Report

Average net farm income was $190,901 in 2008 for the 99 farms included in this annual report of the Southwestern Minnesota Farm Business Management Association. Average earnings decreased by 21$242,267 in 2007 (Figure 1). 2008 ended a steady trend of increasing year-to-year incomes for these farms from 2001 to 2007. Crop farms, with historically high corn and soybean prices, remained very profitable. However, specialized hog farms, which had been very profitable for the past four years, experienced substantial losses. Highlights of association financial results for 2008: Median net farm income was $178,874, slightly lower than the average, indicating that the average was increased by high profits of the most profitable farms. This effect was not as large as previous years, likely because of losses by larger hog operations. • The difference between the most profitable farms and the least profitable continued to increase. The most profitable 20$449,997 while the least profitable lost $-29,476. • Average gross cash income increased by 20$115,999. The average debt-to-asset ratio improved slightly to 39%, down from 40% (Figure 4). • Corn yields were up but soybean yields were down. Corn averaged 172 bushels per acre compared to 162 in 2007. Soybeans yields decreased to 44 bushels from 49 in 2007 (Figure 5). • Both corn and soybean prices received increased by over 50% to $4.51 for corn and$10.83 for soybeans. • The cost to raise an acre of corn (with land rent) increased by 23% while soybean costs increased by 21%. The cost to produce a bushel of corn on cash rented land increased from $2.58 per bushel in 2007 to$2.90 in 2008, while soybean costs per bushel increased from $6.14 to$7.21. • The average specialized hog operation (those with 70% of sales from hogs or pigs) lost over $150,000 in 2008 (Figure 6). All other farm types with enough farms to report averaged net incomes very close to the association average. • Based on rate of return on assets, crop farms (those with 70$1,000,000, were the least profitable based on rate of return on assets. This group earned an average ROA of 7% compared to 14% for farms that grossed between $500,000 and$1,000,000. • With exceptionally high feed prices, no hog or beef enterprise, with the exception of contract growing of hogs (where the contractor provided the feed) covered even direct costs of production. The report provides additional information on profitability, liquidity, and solvency as well as other whole-farm information and detailed information on crop and livestock enterprises. Also reported are whole-farm financial condition and performance by county, sales size class, type of farm, debt-to-asset ratio, and age of operator.Agricultural Finance, Farm Management,

The Desert Hot Springs earthquakes and their tectonic environment

The Desert Hot Springs earthquake of December 4, 1948, was one of the larger recorded earthquakes of southern California, and its aftershocks have continued into 1957. The assigned epicenter is 33° 56'.4 N, 116° 23'.1 W; origin time, 15:43:16.7 P.S.T.; magnitude 6 1/2. Arrival times at local and distant stations are consistent with existing travel-time curves, except for anomalous S – P intervals at very near-by temporary stations; these unexplained anomalies cannot be attributed to varying depth of focus. Epicenters of the 72 aftershocks that have been accurately located are concentrated in a zone 18 km. long, parallel to the Mission Creek fault trace indicated by older scarps, but 5 km. north of it. Aftershock activity is markedly concentrated toward the two ends of this line. Location of the main shock suggests that fracturing started near the southeast end and progressed northwest-ward. The ground surface was not broken, except by landslides. Offset of the line of seismic activity from the trace of the Mission Creek fault suggests that the fault plane dips north. This attitude is substantiated not only by field observations, but also by first motions at stations within 6° of the epicenter, which require a combination of thrust-slip and right lateral-slip on a fault dipping north less than 66°. Inasmuch as this fault is not parallel to regional San Andreas trend, such oblique displacement is reasonable and is consistent with the tectonic pattern of other faults in this region. Five groups of earthquakes represent more than 85 per cent of the total strain release since 1933 in the 3,000 sq. km. area surrounding Desert Hot Springs. These earthquakes, in addition to the Desert Hot Springs shock, are: Morongo Valley (1947), Kitching Peak (1944), Covington Flat (1940), and San Gorgonio Mountain (1935); all are associated with known faults. The Morongo Valley earthquakes probably represent fracturing on the segment of the Mission Creek fault adjacent to that broken during the subsequent Desert Hot Springs shock

Relationship between seismicity and geologic structure in the Southern California region

Data from 10,126 earthquakes that occurred in the southern California region between 1934 and 1963 have been synthesized in the attempt to understand better their relationship to regional geologic structure, which is here dominated by a system of faults related mainly to the San Andreas system. Most of these faults have been considered “active” from physiographic evidence, but both geologic and short-term seismic criteria for “active” versus “inactive” faults are generally inadequate. Of the large historic earthquakes that have been associated with surficial fault displacements, most and perhaps all were on major throughgoing faults having a previous history of extensive Quaternary displacements. The same relationship holds for most earthquakes down to magnitude 6.0, but smaller shocks are much more randomly spread throughout the region, and most are not clearly associated with any mappable surficial faults. Virtually all areas of high seismicity in this region fall within areas having numerous Quaternary fault scarps, but not all intensely faulted areas have been active during this particular 29-year period. Strain-release maps show high activity in the Salton trough, the Agua Blanca-San Miguel fault region of Baja California, most of the Transverse Ranges, the central Mojave Desert, and the Owens Valley-southern Sierra Nevada region. Areas of low activity include the San Diego region, the western and easternmost Mojave Desert, and the southern San Joaquin Valley. Because these areas also generally lack Quaternary faults, they probably represent truly stable blocks. In contrast, regions of low seismicity during this period that show widespread Quaternary faulting include the San Andreas fault within and north of the Transverse Ranges, the Garlock fault, and several quiescent zones along major faults within otherwise very active regions. We suspect that seismic quiescence in large areas may be temporary and that they represent likely candidates for future large earthquakes. Without more adequate geodetic control, however, it is not known that strain is necessarily accumulating in all of these areas. Even in areas of demonstrated regional shearing, the relative importance of elastic strain accumulation versus fault slippage is unknown, although slippage is clearly not taking place everywhere along major “active” faults of the region. Recurrence curves of earthquake magnitude versus frequency are presented for six tectonically distinct 8500-km^2 areas within the region. They suggest either that an area of this small size or that a sample period of only 29 years is insufficient for establishing valid recurrence expectancies; on this basis the San Andreas fault would be the least hazardous zone of the region, because only a few small earthquakes have occurred here during this particular period. Although recurrence expectancies apparently break down for these smaller areas, historic records suggest that the calculated recurrence rate of 52 years for M = 8.0 earthquakes for the entire region may well be valid. Neither a fault map nor the 29-year seismic record provides sufficient information for detailed seismic zoning maps; not only are many other geologic factors important in determining seismic risk, but the strain-release or epicenter map by itself may give a partially reversed picture of future seismic expectance. Seismic and structural relationships suggest that the fault theory still provides the most satisfactory explanation of earthquakes in this region

MINNESOTA CURRENT FARM SITUATION

These papers describe the current economic conditions and outline some of the opportunities facing Minnesota farmers as they complete 1998 and develop plans for 1999. The first paper, Prospects For Farm Income in 1998, describes the variation in net farm income farmers in the Southeastern and Southwestern Farm Management Associations have experienced over the past twenty years. The possible effects of 1998's low commodity prices and government program payments on net farm income are discussed in the context of this historical variation. This paper points out that some farmers are experiencing a very good year in 1998, while others may have very low net farm income this year. Those with high incomes in 1998 may be primarily interested in opportunities to enhance their cash flow for 1999, while those experiencing financial stress during 1998 may need to consider a wider range of adjustments as they plan for the coming year. The remaining papers provide information farmers may want to consider as they plan their marketing and financial strategies for the coming year. Financial Management Alternatives outlines a wide range of financial management alternatives that can be used to deal with cash flow problems. Some of these alternatives will be of interest to farmers who have difficulty in projecting a positive net cash flow with the relatively low commodity prices being projected for 1999. Others are of primary interest to farmers who have relatively high debt levels and must find ways to improve both their net cash flow and their debt/asset position. Some observers have suggested that the low commodity prices projected for 1999 may lead to reductions in cash rental rates. The paper, Cropland Rental Market Impacts of Low Crop Prices, discusses a procedure to estimate "fair rental rates", and provides an historical perspective of the impact low commodity prices have had on land rental rates. The remaining two papers, Situation and Outlook For the Livestock Sector, and Considerations in Developing a Corn/Soybean Marketing Plan for 1998/1999, discuss the major factors to evaluate and options to consider in developing a marketing plan for corn, soybeans, hogs and cattle for the coming year.Farm Management,

Building a Mach Zehnder Interferometer with Limited Resources

Interferometers are simple optical devices that function by splitting a coherent light beam. The beam is recombined using beam splitters and mirrors. The addition of the two light beams produces interference patterns in the forms of fringes which can be used to study the path taken by the two beams. This is old technology and we sought to construct an interferometer using rudimentary and cast-off equipment. The purpose is to show that modern physics concepts can be measured inexpensively and by undergraduate student design. Though we had no optics table and or optical mounts, by careful alignment and adjustments to the equipment, we were able to produce fringes whose intensity could measure phase changes of a light beam as it goes through various mediums. We were able to determine and learn more about the properties of light and produce successful results. This demonstrates a method of introducing modern physics lab applications at a low cost

Minimal recorded earthquakes

The magnitude of an earthquake was originally defined (Richter, 1935) as the common logarithm of the maximum displacement, expressed in microns, of the trace written by a standard torsion seismometer at an epicentral distance of 100 kilometers. When this trace amplitude is one micron the magnitude is accordingly zero