3,456 research outputs found
Biological explorations of Sinai: flora and fauna of Wadi Isla and Hebran, St Katherine Protectorate, Egypt
A comprehensive survey was accomplished for two of the most important and beautiful wadis in the Sinai, Wadi Isla & Hebran. The biodiversity of the two wadis are surveyed including plant species and their associated insects, spiders and scorpions. The list includes 20 plant families with 51 species, 8 insect orders with 54 families and 138 species, and 4 arachnid orders with 17 families and 23 species. The highest number of species recorded were Coleoptera and Hymenoptera.Keywords: Biodiversity, checklist, plants, insects, spider
Silicone -Based Equilibrium Sampling of Sediment to Assess the Thermodynamic Potential of Trace-Level Hydrophobic Organic Contaminants to Bioaccumulate
Social environment as a cause of litter loss in laboratory mouse: A behavioural study
Perinatal mortality is a widespread problem in laboratory mouse breeding and is often manifested by the loss of the entire litter within the first days of life. High mortality is an animal health and welfare concern that violates the 3R principles of reduction and refinement. High pup mortality is often considered “normal” in mouse breeding and the underlying causes
are poorly understood. This study investigated the role of the social environment on pup survival and parental behaviour in C57BL/6 mice. Before parturition, multiparous females were allocated to three treatments: single-housing (SH, n=54) or group-housing in trios of two females and a male, with group-housing further divided into trios with (GH1, n=20) or
without (GH0, n=35) the presence of another litter. Mouse behaviour was recorded from 24h before to 24h after parturition. Mouse breeding performance (offspring survival and weight) was analysed using logistic and generalized linear models, and behaviours using logistic and multivariable linear models. We confirmed previous findings of high
mortality rates for all treatments, but the highest rates were found in GH1 where half of the litters were lost entirely. Social environment had an impact on breeding performance. On the one hand, the presence of adult cagemates in GH0 did not affect litter survival nor pup body weight at 20 days. Adult cagemates shared the work of breeding by performing nest
building before and after litter birth, and parental care after birth. GH0 and GH1 dams were less frequently seen performing nest building before and after parturition than SH dams. GH0 and GH1 dams were also less frequently seen inside the nest and performing parental behaviour after parturition than were SH dams. On the other hand, the risks for
litter and pup loss were dramatically increased by 2.3 and 1.8 times, respectively, in GH1 compared to GH0. Parturition lasted longer in GH1 than in GH0 treatment. While dam behaviour did not differ between GH1 and GH0, GH1 adult cagemates spent less time performing parental care than did GH0 cagemates. Plausible reasons for the higher mortality in the presence of another litter are insufficient parental care, competition for milk access, poor nest quality, and crushing of newborns by older pups in the nest. This study indicates that being born in a cage where there is already an older litter, so-called reproductive asynchrony, is a major risk factor for litter loss.The authors would like to thank Paula Sofia Vilares Gouveia and Sara Capas Peneda who participated
in the behavioural analyses, and all the staff at the Biological Support Unit of the Babraham Institute
for their interest and support in the project and the care of the animals. This work was financed by
FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 -
Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by
Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia/Ministério da Ciência,
Tecnologia e Ensino Superior in the framework of the project PTDC/CVT-WEL/1202/2014 (POCI-01-
0145-FEDER-016591)
Snapping Triceps Syndrome: A Rare Cause of Medial Elbow Pain
PURPOSE: Snapping medial triceps is a relatively rare cause of medial elbow pain that occurs when the tricep tendon dislocates over the medial or lateral epicondyle. Physical exams usually demonstrate intermittent medial elbow pain with extreme elbow flexion or extension, however dynamic diagnostic studies allow for direct visualization of the dislocating tricep. This case report adds to the sparse literature on snapping medial triceps. METHODS: We report a rare occurrence of snapping medial triceps in a young female who initially presented with pain at the posteromedial right elbow with extreme flexion and extension. Intermittent snapping of the medial elbow was noted on physical exam. Ultrasound confirmed snapping of the medial triceps head over osteophytes of the posteromedial olecranon. The patient agreed to surgical right medial triceps release with excision of elbow osteophytes. RESULTS: As demonstrated with our case, static diagnostic imaging such as radiographs and MRI may not adequately characterize snapping triceps syndrome. It is crucial for providers to be aware of subtle differences between dynamic and static diagnostics imaging for snapping medial tricep syndrome. Another important diagnostic tools are electrodiagnostic studies, however as displayed with our patient there may be absence of any ulnar neuropathy at the level of the elbow, which could hinder providers from concerning snapping medial tricep syndrome. CONCLUSION: It is important to consider a broad differential that includes snapping triceps syndrome in a patient presenting with medial elbow pain. EMG and ultrasonography can be useful in differentiating snapping medial triceps from ulnar nerve instability. Treatment can include activity modification, elbow splinting, or surgical release of the snapping part of the triceps
Associations of vitamin D pathway genes with circulating 25-hydroxyvitamin-D, 1,25-dihydroxyvitamin-D, and prostate cancer:a nested case-control study
Vitamin D pathway single nucleotide polymorphisms (SNPs) are potentially useful proxies for investigating whether circulating vitamin D metabolites [total 25-hydroxyvitamin-D, 25(OH)D; 1,25-dihydroxyvitamin, 1,25(OH)2D] are causally related to prostate cancer. We investigated associations of sixteen SNPs across seven genes with prostate-specific antigen-detected prostate cancer
The importance of the weak: Interaction modifiers in artificial spin ices
The modification of geometry and interactions in two-dimensional magnetic
nanosystems has enabled a range of studies addressing the magnetic order,
collective low-energy dynamics, and emergent magnetic properties, in e.g.
artificial spin ice structures. The common denominator of all these
investigations is the use of Ising-like mesospins as building blocks, in the
form of elongated magnetic islands. Here we introduce a new approach: single
interaction modifiers, using slave-mesospins in the form of discs, within which
the mesospin is free to rotate in the disc plane. We show that by placing these
on the vertices of square artificial spin ice arrays and varying their
diameter, it is possible to tailor the strength and the ratio of the
interaction energies. We demonstrate the existence of degenerate ice-rule
obeying states in square artificial spin ice structures, enabling the
exploration of thermal dynamics in a spin liquid manifold. Furthermore, we even
observe the emergence of flux lattices on larger length-scales, when the energy
landscape of the vertices is reversed. The work highlights the potential of a
design strategy for two-dimensional magnetic nano-architectures, through which
mixed dimensionality of mesospins can be used to promote thermally emergent
mesoscale magnetic states.Comment: 17 pages, including methods, 4 figures. Supplementary information
contains 16 pages and 15 figure
Pengaruh Injeksi Co2 Terhadap Biomassa, Total Lipid Dan Profil Asam Lemak Mikroalga Chaetoceros Calcitrans
Mikroalga merupakan mikroorganisme prokariotik atau eukariotik yang dapat
berfotosintesis dan tumbuh dengan cepat pada kondisi yang tidak optimal (Mata et al., 2010).
Pemanfaatan mikroalga, dalam bidang farmakologi meliputi antibakteri, antioksidan, antijamur,
dan antivirus (Chang et al., 1993). Mikroalga juga merupakan sumber protein dalam budidaya
larva udang maupun ikan (Ikhsan et al., 2006).
Mikroalga tergolong dalam organisme yang bersifat autotrof dan memiliki kemampuan
melakukan konversi karbondioksida yang berpotensi menjadi biofuel, makanan, serta bioaktif
yang bernilai tinggi dengan bantuan sinar matahari (Lorenz and Cysewski, 2003; Metzer and
Largeau, 2005; Walter et al., 2005; Spolaore et al., 2016). Mikroalga mengandung protein, lemak,
asam lemak, pigmen dan vitamin. Kandungan lemak (lipid) dan asam lemak (fatty acid) yang ada
dalam mikroalga merupakan sumber energi. Kandungan ini dihasilkan dari proses fotosintesis
berupa hidrokarbon (Prince dan Haroon, 2005). Hal ini juga dapat membantu pengendalian
masalah Gas Rumah Kaca yang semakin meningkat di atmosfer, yang menjadi tantangan besar
bagi dunia yang pro lingkungan dan berkelanjutan (Zeng et al., 2011).
Adapun tujuan dilaksanakannya penelitian ini adalah untuk mengetahui pengaruh
konsentrasi karbondioksida (CO2) yang berbeda terhadap kelimpahan sel dan biomassa
mikroalga, total lipid dan komposisi asam lemak Chaetoceros calcitrans. Penelitian dilakukan
dengan metode eksperimen mengunakan Rancangan Acak Lengkap dengan 5 perlakuan dan 4
ulangan.
Berdasarkan hasil penelitian pertumbuhan tertinggi dengan perlakuan konsentrasi CO2
10% dan terendah pada perlakuan 40% CO2. Biomassa tertinggi ditemukan pada perlakuan
konsentrasi CO2 10% yang juga merupakan yang memiliki laju pertumbuhan spesifik tertinggi
pada hari ke dua. Pertumbuhan maksimal ditemukan pada hari ke 8 yaitu 7,92x106, biomassa
tertinggi didapat dengan perlakuan konsentrasi CO2 yaitu 0,81 gr/l. Kandungan Lipid tertinggi
ditemukan pada perlakuan konsentrasi CO2 10% yaitu 52% berat kering dan terendah pada
perlakuan kontrol yaitu 23,37% berat kering. Biofiksasi CO2 terbaik juga ditemukan pada
perlakuan konsentrasi CO2 30%, hal ini disebabkan masih dalam batas toleransi pertumbuhan
sehingga dapat di fiksasi secara maksimal. Komposisi asam lemak tertinggi yang ditemukan
dalam penelitian adalah jenis asam lemak MUFA dan PUFA. Asam lemak Omega-3 dari berbagai
perlakuan dengan penambahan konsentrasi CO2 pada Chaetoceros calcitrans termasuk EPA
(Eicosapentaenoat) dan DHA (Docosaheksaenoat) sangat bervariasi sedangkan pada perlakuan
kontrol tidak terdapat asam lemak omega-3 jenis DP
Sex-biased parental care and sexual size dimorphism in a provisioning arthropod
The diverse selection pressures driving the evolution of sexual size dimorphism (SSD) have long been debated. While the balance between fecundity selection and sexual selection has received much attention, explanations based on sex-specific ecology have proven harder to test. In ectotherms, females are typically larger than males, and this is frequently thought to be because size constrains female fecundity more than it constrains male mating success. However, SSD could additionally reflect maternal care strategies. Under this hypothesis, females are relatively larger where reproduction requires greater maximum maternal effort – for example where mothers transport heavy provisions to nests.
To test this hypothesis we focussed on digger wasps (Hymenoptera: Ammophilini), a relatively homogeneous group in which only females provision offspring. In some species, a single large prey item, up to 10 times the mother’s weight, must be carried to each burrow on foot; other species provide many small prey, each flown individually to the nest.
We found more pronounced female-biased SSD in species where females carry single, heavy prey. More generally, SSD was negatively correlated with numbers of prey provided per offspring. Females provisioning multiple small items had longer wings and thoraxes, probably because smaller prey are carried in flight.
Despite much theorising, few empirical studies have tested how sex-biased parental care can affect SSD. Our study reveals that such costs can be associated with the evolution of dimorphism, and this should be investigated in other clades where parental care costs differ between sexes and species
Variable strength of forest stand attributes and weather conditions on the questing activity of Ixodes ricinus ticks over years in managed forests
Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming
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