Relative Volume of the Cerebellum in Dolphins and Comparison with Anthropoid Primates

According to the ‘developmental constraint hypothesis’ of comparative mammalian neuroanatomy, brain growth follows predictable allometric trends. Therefore, brain structures should scale to the entire brain in the same way across mammals. Evidence for a departure from this pattern for cerebellum volume has recently been reported among the anthropoid primates. One of the mammalian groups that has been neglected in tests of the ‘developmental constraint hypothesis’ is the cetaceans (dolphins, whales, and porpoises). Because many cetaceans possess relative brain sizes in the range of primates comparative tests of the ‘developmental constraint hypothesis’ across these two groups could help to delineate the parameters of this hypothesis. In this paper, we compare relative cerebellum volumes in two cetacean species, the bottlenose dolphin (Tursiops truncatus) and the common dolphin (Delphinus delphis), with published data from anthropoid primates. We found that relative cerebellum size is significantly greater in the two dolphin species than in any of the primates, including humans. These results suggest that there is possibly expansion of brain structures independent of strictly allometric processes

Pattern of Pathogens and Their Sensitivity Isolated from Surgical Site Infections at the Aga Khan University Hospital, Nairobi, Kenya

Background: In low income countries, surgical site infections (SSIs) are costly and impose a heavy and potentially preventable burden on both patients and healthcare providers. This study aimed to determine the occurrence of SSI, pathogens associated with SSI, the antibiogram of the causative pathogens and specific risk factors associated with SSI at the hospital. Methods: Two hundred and sixty-eight respondents admitted for general surgical procedures (other than neurological and cardiothoracic surgeries) at the Aga Khan University Hospital were eligible to take part in the study. Post-surgery patients were observed for symptoms of infection. Follow ups were done through the consulting clinics, breast clinic and casualty dressing clinic by a team of surgeons. In cases of infection, pus swabs were collected for culture.Results: SSI incidence rate was 7.0%, pathogens isolated from SSI included gram negative enteric bacilli and S. aureus which was the most prevalent bacterial isolate. Only one isolate of MRSA was found and all staphylococci were susceptible to Vancomycin. Preoperative stay ≥ 2 days and wound class were the risk factors associated with SSI.Conclusions: The SSI incidence rates (7.0%) observed in this study were relatively lower than the ones documented in other studies in Kenya. S. aureus is the most prevalent pathogen associated with SSI. Similar to findings from other studies done in the region; prolonged hospital stay and dirty wounds were the risks associated with postsurgical sepsis at the hospital.Keywords: Surgical sites, Infection, Surveillance, Antibiotic

Present status of perch fishery resources in India and its prospects

The perch resources and fisheries In India have been dealt with. As seen from the statewise perch production during 1969-19Q1, on an average 27,184 tonnes of parches were landed in India with fluctuation from 12,865 In 1969 to 49,312 in 1978. The gearwise and statewise perch production from 1982-83 to 1984-85 indicates that the mechanised units contributed 72.4 % and nonmechanised 27.6 %. Among mechanised units, the trawlers have landed the major portion of the catch (68 4 % ) . The State wise species composition of perch landings indicate that the threadtin breams formed more than 50% of the catch- During 1982-83 and 1S83-84. the perch production of Tamil Nadu was higher than all other states whereas during 1984 85, Kerala was the first in perch production followed by Andhrapradesh and Tamil Nadu- The different groups of perches landed by trawl and gill net units at different important landing centres on the east and west coast of Indian show that in all the centres the catch rates of trawlers were higher. The higher catch rate in trawl net operations In Sasoons Dock and New ferry Wharf was due to voyage fishing for more than a da

Effect of Charge Fluctuations on the Persistent Current through a Quantum Dot

We study coherent charge transfer between an Aharonov-Bohm ring and a side-attached quantum dot. The charge fluctuation between the two sub-structures is shown to give rise to algebraic suppression of the persistent current circulating the ring as the size of the ring becomes relatively large. The charge fluctuation at resonance provides transition between the diamagnetic and the paramagnetic states. Universal scaling, crossover behavior of the persistent current from a continuous to a discrete energy limit in the ring is also discussed.Comment: 5 pages, 4 figure

Marine fish calendar. 6. Tuticorin

Tuticorin is one of the well known, age old, fishery ports of India especially by virtue of the production of valuable, good quality, natural pearls and chanks in addition to marine fish production. Early in the 19I1-'15 periods the marine fish production here was to the tune of 663,592 pounds (296.3 tonnes). The fishermen strength was 520 who operated conventional 'valavalai', 'kolavalai', 'madivalai', offshore lining, inshore lining, trolling and other minor nets with the traditional fishing crafts like Tuticorin type of plank built boats called 'Vallam' and 'catamarans'. Over the two decades, mechanized fishing has changed not only the fishing pattern but also the constituent catches. The progress of fishing industry can still be augmented by motorising the plank built boats and 'catamarans'. Present assessment of fishery resources reveals that in a year 19,850 t of fish are landed by trawlers and 9,275 t by traditional fishing units

Semi-invariants of symmetric quivers of finite type

Let $(Q,\sigma)$ be a symmetric quiver, where $Q=(Q_0,Q_1)$ is a finite quiver without oriented cycles and $\sigma$ is a contravariant involution on $Q_0\sqcup Q_1$. The involution allows us to define a nondegenerate bilinear form on a representation $V$ of $Q$. We shall call the representation orthogonal if is symmetric and symplectic if $$ is skew-symmetric. Moreover we can define an action of products of classical groups on the space of orthogonal representations and on the space of symplectic representations. For symmetric quivers of finite type, we prove that the rings of semi-invariants for this action are spanned by the semi-invariants of determinantal type $c^V$ and, in the case when matrix defining $c^V$ is skew-symmetric, by the Pfaffians $pf^V$

Spin Fluctuation Induced Dephasing in a Mesoscopic Ring

We investigate the persistent current in a hybrid Aharonov-Bohm ring - quantum dot system coupled to a reservoir which provides spin fluctuations. It is shown that the spin exchange interaction between the quantum dot and the reservoir induces dephasing in the absence of direct charge transfer. We demonstrate an anomalous nature of this spin-fluctuation induced dephasing which tends to enhance the persistent current. We explain our result in terms of the separation of the spin from the charge degree of freedom. The nature of the spin fluctuation induced dephasing is analyzed in detail.Comment: 4 pages, 4 figure

Mutations in the IGF-II pathway that confer resistance to lytic reovirus infection

BACKGROUND: Viruses are obligate intracellular parasites and rely upon the host cell for different steps in their life cycles. The characterization of cellular genes required for virus infection and/or cell killing will be essential for understanding viral life cycles, and may provide cellular targets for new antiviral therapies. RESULTS: A gene entrapment approach was used to identify candidate cellular genes that affect reovirus infection or virus induced cell lysis. Four of the 111 genes disrupted in clones selected for resistance to infection by reovirus type 1 involved the insulin growth factor-2 (IGF-II) pathway, including: the mannose-6-phosphate/IGF2 receptor (Igf2r), a protease associated with insulin growth factor binding protein 5 (Prss11), and the CTCF transcriptional regulator (Ctcf). The disruption of Ctcf, which encodes a repressor of Igf2, was associated with enhanced Igf2 gene expression. Plasmids expressing either the IGF-II pro-hormone or IGF-II without the carboxy terminal extension (E)-peptide sequence independently conferred high levels of cellular resistance to reovirus infection. Forced IGF-II expression results in a block in virus disassembly. In addition, Ctcf disruption and forced Igf2 expression both enabled cells to proliferate in soft agar, a phenotype associated with malignant growth in vivo. CONCLUSION: These results indicate that IGF-II, and by inference other components of the IGF-II signalling pathway, can confer resistance to lytic reovirus infection. This report represents the first use of gene entrapment to identify host factors affecting virus infection. Concomitant transformation observed in some virus resistant cells illustrates a potential mechanism of carcinogenesis associated with chronic virus infection

Combinatorial realizations of crystals via torus actions on quiver varieties

Consider Kashiwara's crystal associated to a highest weight representation of a symmetric Kac-Moody algebra. There is a geometric realization of this object using Nakajima's quiver varieties, but in many particular cases it can also be realized by elementary combinatorial methods. Here we propose a framework for extracting combinatorial realizations from the geometric picture: We construct certain torus actions on the quiver varieties and use Morse theory to index the irreducible components by connected components of the subvariety of torus fixed points. We then discuss the case of affine sl(n). There the fixed point components are just points, and are naturally indexed by multi-partitions. There is some choice in our construction, leading to a family of combinatorial models for each highest weight crystal. Applying this construction to the crystal of the fundamental representation recovers a family of combinatorial realizations recently constructed by Fayers. This gives a more conceptual proof of Fayers' result as well as a generalization to higher level. We also discuss a relationship with Nakajima's monomial crystal.Comment: 23 pages, v2: added Section 8 on monomial crystals and some references; v3: many small correction

Spectroscopy of 24Al and extraction of Gamow-Teller strengths with the 24Mg(3He,t) reaction at 420 MeV

The 24Mg(3He,t)24Al reaction has been studied at E(3He)=420 MeV. An energy resolution of 35 keV was achieved. Gamow-Teller strengths to discrete levels in 24Al are extracted by using a recently developed empirical relationship for the proportionality between Gamow-Teller strengths and differential cross sections at zero momentum transfer. Except for small discrepancies for a few weak excitations, good agreement with previous 24Mg(p,n) data and nuclear-structure calculations using the USDA/B interactions in the sd shell-model space is found. The excitation energy of several levels in 24Al of significance for determination of the 23Mg(p,gamma)24Al thermonuclear reaction rate were measured. Results are consistent with two of the three previous (3He,t) measurements, performed at much lower beam energies. However, a new state at Ex(24Al)=2.605(10) MeV was found and is the third state above the proton separation energy.Comment: 6 pages, 4 figure