Reclaiming Lost Territory: The Response of Owyhee Harvester Ants to Forager Intrusions by Neighboring Colonies

Neighboring colonies of the Owyhee harvester ant, Pogonomyrmex salinus, often share nonoverlapping foraging boundaries in the areas between their nests. We found that interactions between neighbors along these foraging boundaries were infrequent but peaceful, and usually resulted in one or both individuals becoming agitated and scurrying away in opposite directions. Interactions between neighbors were necessary to maintain the foraging ranges of their respective colonies. An exclusion experiment showed that when one colony of a pair situated 5-7 m apart was denied access to its foraging range, individuals from the other colony would usually (i.e., in 7 out of 10 cases) enter the unoccupied space within one day. In 6 of 7 of those cases the occupiers set up foraging trails in the newly acquired area in 5 to 39 days (median = 13 days). When foragers from the excluded colony were subsequently allowed access to their original foraging area, theyreclaimed the entire area within 11 days but did not extend their advances beyond the original foraging boundaries. In contrast to the earlier encounters between neighbors, encounters during the reacquisition period were always aggressive, and in 14 of 57 encounters one or both of the combatants was killed. Non-lethal contests were shorter duration than lethal contests (19±2 s versus 422±65 s, respectively). Our results show that competition for foraging space in Owyhee harvester ants is intense despite the seemingly peaceful relationship between neighboring colonies prior to perturbation of their foraging boundaries

CAD techniques for microwave circuits

In little more than 10 years computer-aided design (CAD) of microwave circuits has moved from dumb terminals on mainframe computers to PCs, and now to powerful RISC workstations. Commercial CAD software now integrates the various stages of microwave circuit design: schematic capture, simulation and layout. This paper reviews the different CAD packages that are available for microwave circuit design. The basic principles employed in the modelling of microstrip circuits are introduced and the reasons for the extensive use of frequency-domain simulations are explored. The developments in nonlinear, electromagnetic and system-level simulation methods are described.The authors would like to acknowledge the financial support of the Engineering and Physical Sciences Research Council, and the Comisidn Interministerial de Ciencia y Technologia (CICr?‘), Spain, under the project TIC95-0983-C03-02. We would like to thank Hewlett Packard, Barnard Microsystems, Sonnet Software, Optimization Systems Associates, Kimberley Communications Consultants and Ansoft Corporation for their generous educational discounting. The assistance of Dr. D. M. Brookbanks at GEC-Marconi Materials Technology Ltd. (Caswell) is gratefully acknowledged

VPH-2 Risk Factor Analysis for the Transmission of Classical Swine Fever in West Timor, Indonesia

Classical Swine Fever (CSF) is a serious and highly infectious viral disease of domestic pigs and wild boar (Paton and Greiser-Wilke 2003). The causative agent, Classical Swine Fever Virus (CSFV) is a small (40±60 nm) enveloped ribonucleic acid (RNA) virus with a single stranded genome with positive polarity (Horzinek et al. 1971; Moennig and Greiser-Wilke 2008). The virus is one of three pestiviruses that forms a group of economically important pathogens (Moennig et al. 1990) belonging to the Flaviviridae family. It has a close antigenic relationship with the other pestiviruses - bovine viral diarrhoea virus (BVDV) and border disease virus (BDV), as demonstrated by immunodiffusion and immunofluorescence tests, and their similar morphology and nucleic acid homology (Wengler 1991; Wengler et al. 1995). Indonesia was free from CSF until 1993. Between 1994 and 1996 thousands of pigs were reported to have died from the disease in the Indonesian regions of North Sumatera, Jakarta, Bali, Central Java, and North Sulawesi (Satya and Santhia 2000). An outbreak of CSF was reported in Dili, East Timor in August 1997 and the disease then spread to the Kupang district of West Timor in March 1998 (Satya and Santhia 2009) and subsequently to all districts of Timor (Santhia et al. 1997; Santhia et al. 1998).              The existence of CSF in an area and the potential for introducing the disease into a new area can be associated with the presence of certain risk factors. Identification of these risk factors is important in understanding the transmission of disease and for developing effective prevention, control and eradication programs. Farmers are a valuable source of information about potential risk factors and associated management and husbandry practices linked with disease as they often have many years of experience in raising or trading livestock. This knowledge can be used to identify risk factors for disease.The objective of the study was to identify potential risk factors associated with CSF infection in West Timor. In particular factors involved in the management and husbandry of pigs were investigated

Harmonic suppression in microstrip dual-mode ring-resonator bandpass filters

This paper introduces two new topologies for rejecting the harmonics in microstrip ring resonator filters. First one uses 50 Ω spur line filter structures placed at the input and output of the ring to suppress the first harmonic. Second topology incorporates low-pass structures into the ring for elimination of the harmonic

Constraining C iii] Emission in a Sample of Five Luminous z = 5.7 Galaxies

Recent observations have suggested that the CIII]$\lambda1907/1909$ emission lines could be alternative diagnostic lines for galaxies in the reionization epoch. We use the F128N narrowband filter on the Hubble Space Telescope's ($\it{HST}$) Wide Field Camera 3 (WFC3) to search for CIII] emission in a sample of five galaxies at z = 5.7 in the Subaru Deep Field and the Subaru/XMM-Newton Deep Field. Using the F128N narrowband imaging, together with the broadband imaging, we do not detect CIII] emission for the five galaxies with $J_{\rm{AB}}$ ranging from 24.10 -- 27.00 in our sample. For the brightest galaxy J132416.13+274411.6 in our sample (z = 5.70, $J_{\rm{AB}} = 24.10$), which has a significantly higher signal to noise, we report a CIII] flux of $3.34\pm1.81 \times 10^{-18}$ $\mathrm{erg\ s^{-1}\ cm^{-2}}$, which places a stringent 3-$\rm\sigma$ upper limit of $5.43\times 10^{-18}$ $\mathrm{erg\ s^{-1}\ cm^{-2}}$on CIII] flux and 6.57 \AA\ on the CIII] equivalent width. Using the stacked image, we put a 3-$\rm\sigma$upper limit on the mean CIII] flux of$\mathrm{2.55\times10^{-18}\ erg\ s^{-1}\ cm^{-2}}$, and a 3-$\rm\sigma$upper limit on the mean CIII] equivalent width of 4.20 {\AA} for this sample of galaxies at z = 5.70. Combined with strong CIII] detection reported among high-z galaxies in the literature, our observations suggest that the equivalent widths of CIII] from galaxies at z$>$ 5.70 exhibit a wide range of distribution. Our strong limits on CIII] emission could be used as a guide for future observations in the reionization epoch

Minds in skilled performance: From phenomenology to cognitive explanations

Performing successfully, in any domain, depends on being in the right state of mind. An experienced athlete might fail to make a well-practiced move distracted by a fellow athlete\u27s unsolicited advice given to her in the last minute before the game. An expert driver may fumble at making a simple manoeuvre, distracted by the pain developing in his lower back after hours of driving. A student can fail at a math test despite his devoted preparation, his nerves getting the better of him on the test day. Such occurrences are all too familiar. But what exactly goes wrong in all these cases? Characterizing the right state of mind needed for skilled performance poses a vexing theoretical challenge

A response to “Likelihood ratio as weight of evidence: a closer look” by Lund and Iyer

Recently, Lund and Iyer (L&I) raised an argument regarding the use of likelihood ratios in court. In our view, their argument is based on a lack of understanding of the paradigm. L&I argue that the decision maker should not accept the expert’s likelihood ratio without further consideration. This is agreed by all parties. In normal practice, there is often considerable and proper exploration in court of the basis for any probabilistic statement. We conclude that L&I argue against a practice that does not exist and which no one advocates. Further we conclude that the most informative summary of evidential weight is the likelihood ratio. We state that this is the summary that should be presented to a court in every scientific assessment of evidential weight with supporting information about how it was constructed and on what it was based

Submaximal Oviposition Rates in a Mymarid Parasitoid: Choosiness Should Not Be Ignored

Cronin and Strong (1993a, b) examined the oviposition behavior of Anagarus delicatus Dozier (Hymenoptera: Mymaridae), an egg parasitoid of the leafhopper Prokelisia marginate Van Duzee (Homoptera: Delphacidae). They reported oviposition rates that were lower than predicted if the rate of egg-laying was maximized. Cronin and Strong (1993a) considered, and subsequently rejected, several “rules of thumb” (Stephens and Krebs 1986) as explanations for the observed patterns of patch departure. They observed that hosts on leaves experience density-independent mortality due to leaf senescence. Based on that, they advanced the hypothesis that submaximal oviposition rates in A. delicatus are best explained as risk-spreading by the parasitoid. (That is, by laying a small number of eggs on many leaves, the parasitoid increases the probability that some of her offspring will survive; Cronin and Strong 1993a.) An alternative hypothesis (Rosenheim and Mangel 1994) suggests that by distributing the eggs among several leaves, A. delicatus avoids self-superparasitism. Here, we take a somewhat different approach than those provided above to explain an additional observation of Cronin and Strong (1993a): female wasps rejected most of the hosts that they had probed. In so doing, we argue that rate maximization was an inappropriate prediction for A. delicatus, and in light of the life history parameters of this species, egg limitation is more suitable. Furthermore, egg limitation, when combined with one of the proposed explanations for the distribution of eggs, can explain the high rejection level of potential hosts