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1. Multiple paternity in a lek mating system: Females mate multiply when they choose inexperienced sires

   https://doi.org/10.1111/1365-2656.13158  

   Rivers, Pearl R. ; DuVal, Emily H. ; Sheldon, ed., Ben ( December 2019 , Journal of Animal Ecology)

   Multiple mating by females is common and often driven by social constraints on female mate choice. However, females mate with multiple males even in systems without these social constraints and rates of multiple mating tend to be highly variable within and between populations. In lek mating systems, females are able to assess multiple males and their choice is unrestricted by pair bonds or the need for biparental care, yet some females mate with multiple males.

   To better understand the factors affecting variation in multiple mating, we investigated the occurrence of multiple paternity within clutches in a highly polygynous lek mating system.

   Using long‐term data on genetic paternity, survival, social status and individual age from a population of lance‐tailed manakinsChiroxiphia lanceolata, a species where males lek in cooperative alpha‐beta pairs, we tested five non‐exclusive hypotheses about the causes of variation in multiple mating and its benefits in females.

   We found that inexperienced males, including new alphas and rare beta sires, were disproportionately likely to share paternity when they sired any chicks. In contrast, female age (experience) was unrelated to multiple paternity. Multiple mating did not result in higher reproductive success or reduced variance in success for females, and there were neither consistently promiscuous females nor males that consistently shared paternity.

   The occurrence of multiple paternity in this lek mating system was best explained by female choice related to male characteristics that change with male experience. Our results support the hypothesis that there is a developmental component to the occurrence of multiple mating, and suggest females choose to mate multiply when their choices are not optimal.

    

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2. One internship, two internships, three internships … more!’: exploring the culture of the multiple internship economy

   https://doi.org/10.1080/13639080.2022.2036713  

   Wolfgram, M. ( January 2022 , Journal of education and work)

   Internships are increasingly promoted as a high impact practice to improve students’ post-graduation employment outcomes, and educators often encourage students to participate in multiple internships. Yet, there is a lack of research on the sociocultural contexts associated with multiple internship participation. We present findings about the culture of multiple internship participation – drawing on focus groups and one-year follow-up interviews with students at five colleges in the United States, along with interviews with their educators and an analysis of online documents about multiple internship participation. The evidence documents a particular culture of the multiple internship economy, representing multiple internships as a linear, progressive, goal-oriented cultural project to accumulate a marketable self; also described by anthropologists as a neoliberal conception of the self. This cultural conception of a marketable neoliberal self is comprised of signs – such as narratives of multiple internships – that provide evidence of skills and experiences, of persevering through obstacles, and of ‘hustle’ and a ‘do what it takes’ attitude, which can be deployed to navigate competitive gatekeeping encounters such as employment interviews. Based on these findings, we develop a sociocultural theory of multiple internship participation as a project of neoliberal gatekeeping navigation. 

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3. Multiple paternity and the number of offspring: A model reveals two major groups of species

   https://doi.org/10.1002/bies.202000247  

   Correia, Hannah E. ; Abebe, Ash ; Dobson, F. Stephen ( January 2021 , BioEssays)

   Parentage analyses via microsatellite markers have revealed multiple paternity within the broods of polytocous species of mammals, reptiles, amphibians, fishes and invertebrates. The widespread phenomenon of multiple paternity may have attending relationships with such evolutionary processes as sexual selection and kin selection. However, just how much multiple paternity should a species exhibit? We developed Bayesian null models of how multiple paternity relates to brood sizes. For each of 114 species with published data on brood sizes and numbers of sires, we compared our null model estimates to published frequencies of multiple paternity. The majority of species fell close to our null model, especially among fish and invertebrate species. Some species, however, had low probabilities of multiple paternity, far from the predictions of the null model, likely due to sexual selection and environmental constraints. We suggest a major division among species’ mating systems between those with close to random mating and high levels of multiple paternity, and those with constraints that produce low levels of multiple paternity.

    

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4. Demonstration of using two aperture pairs combined with multiple-mode receivers and MIMO signal processing for enhanced tolerance to turbulence and misalignment in a 10  Gbit/s QPSK FSO link

   https://doi.org/10.1364/OL.391120  

   Song, Haoqian ; Li, Long ; Pang, Kai ; Zhang, Runzhou ; Zou, Kaiheng ; Zhao, Zhe ; Du, Jing ; Song, Hao ; Liu, Cong ; Cao, Yinwen ; et al ( May 2020 , Optics Letters)

   We utilize aperture diversity combined with multiple-mode receivers and multiple-input-multiple-output (MIMO) digital signal processing (DSP) to demonstrate enhanced tolerance to atmospheric turbulence and spatial misalignment in a 10 Gbit/s quadrature-phase-shift-keyed (QPSK) free-space optical (FSO) link. Turbulence and misalignment could cause power coupling from the fundamental Gaussian mode into higher-order modes. Therefore, we detect power from multiple modes and use MIMO DSP to enhance the recovery of the original data. In our approach, (a) each of multiple transmitter apertures transmits a single fundamental Gaussian beam carrying the same data stream, (b) each of multiple receiver apertures detects the signals that are coupled from the fundamental Gaussian beams to multiple orbital angular momentum (OAM) modes, and (c) MIMO DSP is used to recover the data over multiple modes and receivers. Our simulation shows that the outage probability could be reduced from$><\#comment/>0.1$to$<<\#comment/>0.01$. Moreover, we experimentally demonstrate the scheme by transmitting two fundamental Gaussian beams carrying the same data stream and recovering the signals on OAM modes 0 and$+1$at each receiver aperture. We measure an up to$\sim <\#comment/>10\mathrm{d}\mathrm{B}$power-penalty reduction for a bit error rate (BER) at the 7% forward error correction limit for a 10 Gbit/s QPSK signal.

    

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5. Seismic Imaging across the Northern Chukchi Borderland: Implications of the Canada Basin Opening

   Priyanto, Wisnu ; Coakley, Bernard ( October 2022 , Transactions American Geophysical Union)

   Multichannel-seismic data were collected in August and September 2021 over the Northern Chukchi Borderland and Central Canada Basin from the R/V Sikuliaq. The data were acquired with two 520 cu inch GI airguns and a 200 meters (32 channels) streamer. The preliminary processing started by screening the bad traces caused by the broken hydrophone and misfires during acquisition. Bandpass and F-K filtering were applied to the traces. The bandpass filtering eliminates energy that is outside of the band of energy emitted by the airguns. The F-K filter is implemented by bringing the signal amplitude into the frequency-wavenumber (f-k) domain to exclude the reflection signal with the noise amplitude. Our seismic data contains multiples that interfere with the primary image, obscuring the data. These multiples usually occur when seismic signals are trapped in the water column. We utilized surface related multiple elimination (SRME) method to attenuate the multiples. Surface related multiple elimination is applied by developing multiple prediction models from the primary reflection and generating the high order and low order multiple to subtract or eliminate the multiple. We find the SRME method is improved adjusting the sediment velocity and the filter length. The bandpass and F-K filter show a significant improvement in the signal coherence. The SRME method is effective in improving the clarity and continuity of the primary reflectors. Profiles were generated by performing post-stack time migration. Post-stack migration was applied by summing all the reflected signals into a CDP gather, strengthen the coherent reflectors, then migrating or relocating the dipping reflector to its actual location and eliminating the diffraction effects. We have tied our interpretation to the previous project acquired in 2011 from the southern part of the Chukchi Borderland. The 2011 survey sailed over wells drilled by Shell in the late 80s on the Chukchi Shelf and directly tied the reflectors with the stratigraphy. The processed multichannel-seismic profiles from the Northern Chukchi Borderland show horsts with grabens continuous with those imaged from RV Langseth in 2011. These basins are filled with syn-rift and post-rift stratigraphy. Stratigraphic sequences imaged on Northwind Ridge are segmented by multiple unconformities and minor structures. The origin of these unconformities may be related to the opening of Canada Basin and multiple generations of glacial ice contact over the bathymetric high. The seismic profile on Canada basin showed a prominent feature recognized as a basement, which seems to support the interpretation of the extinct mid-ocean ridge as an unsegmented, ultra-slow spreading ridge. 

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