Echolocation clicks of free-ranging Cuvier's beaked whales (Ziphius cavirostris)

Author Posting. © Acoustical Society of America, 2005. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 117 (2005): 3919-3927, doi:10.1121/1.1910225.Strandings of beaked whales of the genera Ziphius and Mesoplodon have been reported to occur in conjunction with naval sonar use. Detection of the sounds from these elusive whales could reduce the risk of exposure, but descriptions of their vocalizations are at best incomplete. This paper reports quantitative characteristics of clicks from deep-diving Cuvier's beaked whales (Ziphius cavirostris) using a unique data set. Two whales in the Ligurian Sea were simultaneously tagged with sound and orientation recording tags, and the dive tracks were reconstructed allowing for derivation of the range and relative aspect between the clicking whales. At depth, the whales produced trains of regular echolocation clicks with mean interclick intervals of 0.43 s (±0.09) and 0.40 s (±0.07). The clicks are frequency modulated pulses with durations of ~200 µs and center frequencies around 42 kHz, –10 dB bandwidths of 22 kHz, and Q3 dB of 4. The sound beam is narrow with an estimated directionality index of more than 25 dB, source levels up to 214 dBpp re: 1 µPa at 1 m, and energy flux density of 164 dB re: 1 µPa2 s. As the spectral and temporal properties are different from those of nonziphiid odontocetes the potential for passive detection is enhanced.Tag was funded in part by a Cecil H. and Ida M. Green Award and the US Office of Naval Research. WHOI fieldwork and tag development was funded by the National Oceanographic Partnership Program (NOPP), the Strategic Environmental Research and Development Program (SERDP) under Program No. CS-1188, and the Packard Foundation, and was supported by BluWest and the NATO Undersea Research Center

Rooftop Photovoltaics Market Penetration Scenarios

The goal of this study was to model the market penetration of rooftop photovoltaics (PV) in the United States under a variety of scenarios, on a state-by-state basis, from 2007 to 2015

Categorizing click trains to increase taxonomic precision in echolocation click loggers

L.R. and K.J.P. were supported by Marine Scotland Science and the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Passive acoustic monitoring is an efficient way to study acoustically active animals but species identification remains a major challenge. C-PODs are popular logging devices that automatically detect odontocete echolocation clicks. However, the accompanying analysis software does not distinguish between delphinid species. Click train features logged by C-PODs were compared to frequency spectra from adjacently deployed continuous recorders. A generalized additive model was then used to categorize C-POD click trains into three groups: broadband click trains, produced by bottlenose dolphin (Tursiops truncatus) or common dolphin (Delphinus delphis), frequency-banded click trains, produced by Risso's (Grampus griseus) or white beaked dolphins (Lagenorhynchus albirostris), and unknown click trains. Incorrect categorization rates for broadband and frequency banded clicks were 0.02 (SD 0.01), but only 30% of the click trains met the categorization threshold. To increase the proportion of categorized click trains, model predictions were pooled within acoustic encounters and a likelihood ratio threshold was used to categorize encounters. This increased the proportion of the click trains meeting either the broadband or frequency banded categorization threshold to 98%. Predicted species distribution at the 30 study sites matched well to visual sighting records from the region.PostprintPeer reviewe

Exploring the Simultaneous Effect of Total Ion Concentration and K:Ca:Mg Ratio of the Nutrient Solution on the Growth and Nutritional Value of Hydroponically Grown Cichorium spinosum L.

Nutrient-efficient plants and agricultural systems could tackle issues resulting from conventional agriculture. Spiny chicory (Cichorium spinosum L.), a very adaptive, wild edible vegetable, is gaining commercial interest as a functional food. Floating-raft hydroponics is a method commonly used for the commercial cultivation of leafy vegetables due to numerous advantages compared to soil cultivation. In this paper, the simultaneous effects of different potassium, calcium and magnesium ratios and different electrical conductivity (EC) levels on the growth and mineral composition of hydroponically grown C. spinosum were investigated. Four nutrient solutions (NS) were compared, two NS with low EC (L, 2.4 dS/m) and two with high EC (H, 3.6 dS/m) with K:Ca:Mg ratios of either 50:40:10 or 40:50:10. The results showed no interactions between the two factors. No significant effects were observed on the fresh and dry weight, leaf number and leaf area. High EC levels increased the K content and decreased the Mn and Zn content in the leaf tissues. The 40:50:10 ratio led to increased Ca content in plant tissues. The Nitrate-N was only affected by the EC level and was increased under H conditions, whereas the total-N was not affected

Communication cost of channel estimation interpolation for group-based vehicular communications in cellular networks

Las comunicaciones inalámbricas para aplicaciones vehiculares en sistemas celulares de quinta generación (5G) deben ser de baja latencia y alta fiabilidad. Entre otros factores, la cantidad de información de control que debe intercambiarse entre cada vehículo y la estación base puede penalizar la latencia de la comunicación. Varios casos de uso vehicular 5G implican comunicaciones dentro de grupos de vehículos, por ejemplo el pelotón de vehículos. Este trabajo se centra en explotar la estructura y características de este servicio vehicular particular basado en grupos para disminuir el intercambio de información de control relacionado con la etapa de estimación del canal necesaria para las comunicaciones celulares entre vehículos e infraestructura celular. Se propone un esquema basado en la interpolación espacial del canal en el que el canal real sólo está disponible en un subconjunto de vehículos, y la posterior interpolación espacial del canal proporciona estimaciones de los parámetros del canal a gran escala para el resto de vehículos del grupo. En el artículo, se derivan expresiones de coste de comunicación para topologías centralizadas y distribuidas, considerando un escenario con una macro estación base que da servicio a un pelotón de vehículos. Los resultados de la evaluación muestran que la topología distribuida es más eficiente en términos de coste de comunicación, mientras que la arquitectura centralizada centralizada es más robusta frente a las variaciones de distancia entre vehículos. entre vehículos.RYC- 2017-22101UV-SFPIE PID19-1097673.Wireless communications for vehicular applications in fifth generation cellular systems (5G) are required to be of low latency and high reliability. Among other factors, the amount of control information to be exchanged between each vehicle and the base station can penalize the communication latency. Several 5G vehicular use cases involve communications within groups of vehicles, for instance, vehicle platooning. This work is focused on exploiting the structure and characteristics of this particular group-based vehicular service to decrease the control information exchange related to the channel estimation stage necessary for vehicle to infrastructure cellular communications. A scheme based on channel spatial interpolation is proposed, where the real channel is only available at a subset of vehicles, and subsequent spatial interpolation of the channel provides estimates of the large-scale channel parameters for the rest of vehicles in the group. In the paper, communication cost expressions are derived for centralized and distributed topologies, considering a scenario with a macro base station serving a vehicle platoon. The evaluation results show that the distributed topology is more efficient in terms of communication cost, while the centralized architecture is more robust against inter-vehicle distance variations

Genomics reveals the role of admixture in the evolution of structure among sperm whale populations within the Mediterranean Sea

In oceanic ecosystems, the nature of barriers to gene flow and the processes by which populations may become isolated are different from the terrestrial environment, and less well understood. In this study we investigate a highly mobile species (the sperm whale, Physeter macrocephalus) that is genetically differentiated between an open North Atlantic population and the populations in the Mediterranean Sea. We apply high-resolution single nucleotide polymorphism (SNP) analysis to study the nature of barriers to gene flow in this system, assessing the putative boundary into the Mediterranean (Strait of Gibraltar and Alboran Sea region), and including novel analyses on structuring among sperm whale populations within the Mediterranean basin. Our data support a recent founding of the Mediterranean population, around the time of the last glacial maximum, and show concerted historical demographic profiles in both the Atlantic and the Mediterranean. In each region there is evidence for a population decline around the time of the founder event. The largest decline was seen within the Mediterranean Sea where effective population size is substantially lower (especially in the eastern basin). While differentiation is strongest at the Atlantic/Mediterranean boundary, there is also weaker but significant differentiation between the eastern and western basins of the Mediterranean Sea. We propose, however, that the mechanisms are different. While post-founding gene flow was reduced between the Mediterranean and Atlantic populations, within the Mediterranean an important factor differentiating the basins is probably a greater degree of admixture between the western basin and the North Atlantic and some level of isolation between the western and eastern Mediterranean basins. Subdivision within the Mediterranean Sea exacerbates conservation concerns and will require consideration of what distinct impacts may affect populations in the two basins

Dimerisation of the PICTS complex via LC8/Cut-up drives co-transcriptional transposon silencing in Drosophila

In animal gonads, the PIWI-interacting RNA (piRNA) pathway guards genome integrity in part through the co-transcriptional gene silencing of transposon insertions. In Drosophila ovaries, piRNA-loaded Piwi detects nascent transposon transcripts and instructs heterochromatin formation through the Panoramix-induced co-transcriptional silencing (PICTS) complex, containing Panoramix, Nxf2 and Nxt1. Here, we report that the highly conserved dynein light chain LC8/Cut-up (Ctp) is an essential component of the PICTS complex. Loss of Ctp results in transposon de-repression and a reduction in repressive chromatin marks specifically at transposon loci. In turn, Ctp can enforce transcriptional silencing when artificially recruited to RNA and DNA reporters. We show that Ctp drives dimerisation of the PICTS complex through its interaction with conserved motifs within Panoramix. Artificial dimerisation of Panoramix bypasses the necessity for its interaction with Ctp, demonstrating that conscription of a protein from a ubiquitous cellular machinery has fulfilled a fundamental requirement for a transposon silencing complex