ECHOLOCATION IN DOLPHINS WITH A DOLPHIN-BAT COMPARISON

ABSTRACT

Dolphins possess a highly sophisticated auditory system and a keen capability for echolocation. Signals are emitted in the form of high intensity, short duration, broadband exponentially decaying pulses. The frequency spectra of echolocation signals used by many dolphins are dependent on the output intensity of the signals and not on any fine tuning by the animals. When the output intensity is low, the center frequency of the click tends to be low. As the output intensity increases, the center frequency also tends to increase. The pulses propagate from the dolphin's melon in a relatively narrow beam, and echoes are received via the lower jaw, with a slightly wider beam. Echo- locating dolphins can detect targets at ranges of approximately 100 plus meters, depending on the size of the targets. Target discrimination experiments have shown that dolphins can discriminate the shape, size, material composition and internal structure of targets from the echoes. The broadband short duration properties of the signal allow the echoes to have high temporal resolution, so that within the structure of the echoes a considerable amount of information on the properties of the target can be conveyed. A brief comparison between the bat and dolphin sonar system will also be made. Bats typically emit much longer signals and a wider variety of different types of signals than dolphins. Signals used by some bats are suited to detecting Doppler shift, whereas the dolphin signal is designed to be tolerant of Doppler effects.     

Isothermal micro calorimetry - a new method for MIC determinations: results for 12 antibiotics and reference strains of E. coli and S. aureus

Background  

Antimicrobial susceptibility testing of microorganisms is performed by either disc diffusion or broth dilution tests. In clinical use, the tests are often still performed manually although automated systems exist. Most systems, however, are based on turbidometric methods which have well-known drawbacks.     

香港鹅耳枥(桦木科)的群落特征

为保护香港特有植物香港鹅耳枥,基于典型样地调查,对香港鹅耳枥所在群落进行了研究。结果表明,在225 m2的样地内,有维管植物37科66属68种。建群种为香港鹅耳枥,个体高度最高3 m,所在群落植株平均高度0.92 m,分层不明显。位于中国香港岛的香港鹅耳枥处于衰退状态,小个体极少。因此,建议采取就地保护和迁地保护措施,以重建种群。     

基于MODIS-EVI的西南地区植被覆盖时空变化及驱动因素研究

基于MODIS-EVI和气象数据,利用最大值合成法、像元二分模型、趋势分析和相关分析等方法,探讨了西南地区2001-2015年植被覆盖时空变化特征及其对气候因子的响应,并分析了温度和降水对植被覆盖时空变化的驱动作用。结果表明：（1）2001-2015年,西南地区植被EVI以0.1%/a的变化率呈波动增加趋势,但空间异质性显著,呈现出从东南向西北逐渐递减的趋势;（2）西南地区以高和极高植被覆盖度为主,极低植被覆盖度区域约占研究区总面积的8.6%,植被覆盖度增加的区域集中分布在广西省北海-钦州、贵州省邵通-毕节-遵义、四川省广元-广安以及西藏那曲等地区,植被覆盖度呈减少趋势区域主要集中在西藏拉萨-阿里地区和四川成都-阿坝州-甘孜州等地区;（3）植被EVI与同期温度和降水相关性较好,均以正相关为主。在0.05显著水平下,受降水驱动的区域呈斑块状分布在西藏自治区和青海省交界处,以及云南和广西部分地区,约占研究区总面积的3.4%;受温度驱动的区域零星分布在各省、自治区,约占研究区总面积的1.6%;受温度和降水共同驱动的区域约占研究区总面积的7.2%,主要分布在西藏自治区的阿里地区北部,青海省的三江源地区以及四川和贵州两省交界处的小部分地区;西南地区大部分区域的植被EVI指数变化表现为非气候因素驱动。     

Hidden Concepts in the History and Philosophy of Origins-of-Life Studies: a Workshop Report

Origins of Life and Evolution of Biospheres - In this review, we describe some of the central philosophical issues facing origins-of-life research and provide a targeted history of the developments...     

Plant as a plenteous reserve of lectin

Lectins are clusters of glycoproteins of nonimmune foundation that combine specifically and reversibly to carbohydrates, mainly the sugar moiety of glycoconjugates, resulting in cell agglutination and precipitation of glycoconjugates. They are universally distributed in nature, being established in plants, fungi, viruses, bacteria, crustacea, insects, and animals, but leguminacae plants are rich source of lectins. The present review reveals the structure, biological properties, and application of plant lectins.     

Rolling stones and stable homes: social structure,habitat diversity and population genetics of the Hawaiian spinner dolphin (Stenella longirostris)

Spinner dolphins (Stenella longirostris) exhibit different social behaviours at two regions in the Hawaiian Archipelago: off the high volcanic islands in the SE archipelago they form dynamic groups with ever‐changing membership, but in the low carbonate atolls in the NW archipelago they form long‐term stable groups. To determine whether these environmental and social differences influence population genetic structure, we surveyed spinner dolphins throughout the Hawaiian Archipelago with mtDNA control region sequences and 10 microsatellite loci (n = 505). F‐statistics, Bayesian cluster analyses, and assignment tests revealed population genetic separations between most islands, with less genetic structuring among the NW atolls than among the SE high islands. The populations with the most stable social structure (Midway and Kure Atolls) have the highest gene flow between populations (mtDNA Φ_ST < 0.001, P = 0.357; microsatellite F_ST = ?0.001; P = 0.597), and a population with dynamic groups and fluid social structure (the Kona Coast of the island of Hawai’i) has the lowest gene flow (mtDNA 0.042 < Φ_ST < 0.236, P < 0.05; microsatellite 0.016 < F_ST < 0.040, P < 0.001). We suggest that gene flow, dispersal, and social structure are influenced by the availability of habitat and resources at each island. Genetic comparisons to a South Pacific location (n = 16) indicate that Hawaiian populations are genetically depauperate and isolated from other Pacific locations (mtDNA 0.216 < F_ST < 0.643, P < 0.001; microsatellite 0.058 < F_ST < 0.090, P < 0.001); this isolation may also influence social and genetic structure within Hawai’i. Our results illustrate that genetic and social structure are flexible traits that can vary between even closely‐related populations.     

Origins of Life Research: a Bibliometric Approach

This study explores the collaborative nature and interdisciplinarity of the origin(s) of life (OoL) research community. Although OoL research is one of the oldest topics in philosophy, religion, and science; to date there has been no review of the field utilizing bibliometric measures. A dataset of 5647 publications that are tagged as OoL, astrobiology, exobiology, and prebiotic chemistry is analyzed. The most prolific authors (Raulin, Ehrenfreund, McKay, Cleaves, Cockell, Lazcano, etc.), most cited scholars and their articles (Miller 1953, Gilbert 1986, Chyba & Sagan 1992, W?chtersh?user 1988, etc.), and popular journals (Origins of Life and Evolution of Biospheres and Astrobiology) for OoL research are identified. Moreover, interdisciplinary research conducted through research networks, institutions (NASA, Caltech, University of Arizona, University of Washington, CNRS, etc.), and keywords & concepts (astrobiology, life, Mars, amino acid, prebiotic chemistry, evolution, RNA) are explored.     

Data sharing by scientists: practices and perceptions

Background

Scientific research in the 21st century is more data intensive and collaborative than in the past. It is important to study the data practices of researchers – data accessibility, discovery, re-use, preservation and, particularly, data sharing. Data sharing is a valuable part of the scientific method allowing for verification of results and extending research from prior results.

Methodology/Principal Findings

A total of 1329 scientists participated in this survey exploring current data sharing practices and perceptions of the barriers and enablers of data sharing. Scientists do not make their data electronically available to others for various reasons, including insufficient time and lack of funding. Most respondents are satisfied with their current processes for the initial and short-term parts of the data or research lifecycle (collecting their research data; searching for, describing or cataloging, analyzing, and short-term storage of their data) but are not satisfied with long-term data preservation. Many organizations do not provide support to their researchers for data management both in the short- and long-term. If certain conditions are met (such as formal citation and sharing reprints) respondents agree they are willing to share their data. There are also significant differences and approaches in data management practices based on primary funding agency, subject discipline, age, work focus, and world region.

Conclusions/Significance

Barriers to effective data sharing and preservation are deeply rooted in the practices and culture of the research process as well as the researchers themselves. New mandates for data management plans from NSF and other federal agencies and world-wide attention to the need to share and preserve data could lead to changes. Large scale programs, such as the NSF-sponsored DataNET (including projects like DataONE) will both bring attention and resources to the issue and make it easier for scientists to apply sound data management principles.