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1Latest Papers from Table of Contents or Articles in PressN. L. Stephenson ; A. J. Das ; R. Condit ; S. E. Russo ; P. J. Baker ; N. G. Beckman ; D. A. Coomes ; E. R. Lines ; W. K. Morris ; N. Ruger ; E. Alvarez ; C. Blundo ; S. Bunyavejchewin ; G. Chuyong ; S. J. Davies ; A. Duque ; C. N. Ewango ; O. Flores ; J. F. Franklin ; H. R. Grau ; Z. Hao ; M. E. Harmon ; S. P. Hubbell ; D. Kenfack ; Y. Lin ; J. R. Makana ; A. Malizia ; L. R. Malizia ; R. J. Pabst ; N. Pongpattananurak ; S. H. Su ; I. F. Sun ; S. Tan ; D. Thomas ; P. J. van Mantgem ; X. Wang ; S. K. Wiser ; M. A. Zavala
Nature Publishing Group (NPG)
Published 2014Staff ViewPublication Date: 2014-01-17Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Aging/metabolism ; Biomass ; *Body Size ; Carbon/*metabolism ; *Carbon Cycle ; Climate ; Geography ; Models, Biological ; Plant Leaves/growth & development/metabolism ; Sample Size ; Species Specificity ; Time Factors ; Trees/*anatomy & histology/classification/growth & development/*metabolism ; Tropical ClimatePublished by: -
2Articles: DFG German National LicensesStaff View
ISSN: 0028-3932Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: PsychologyType of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesStaff View
ISSN: 1420-8954Keywords: Keywords. Cryptography, private protocols, randomness, information theory, entropy.Source: Springer Online Journal Archives 1860-2000Topics: Computer ScienceNotes: Abstract. We consider the problem of n honest but curious players with private inputs $ x_1,\ldots,x_n, $ who wish to compute the value of a fixed function $ {\cal F}(x_1,\ldots,x_n) $ in such way that at the end of the protocol every player knows the value $ {\cal F}(x_1,\ldots,x_n) $ . Each pair of players is connected by a secure point-to-point communication channel. The players have unbounded computational resources and they intend to compute $ {\cal F} $ in a t-private way. That is, after the execution of the protocol, no coalition of size at most $ t \le n - 1 $ can get any information about the inputs of the remaining players other than what can be deduced from their own inputs and the value of $ \cal F $ .¶ We study the amount of randomness needed in t-private protocols. We prove a lower bound on the randomness complexity of any t-private protocol to compute a function with sensitivity n. As a corollary, we obtain that when the private inputs are uniformly distributed, at least k(n—1)(n—2)/2 random bits are needed to compute the sum modulo 2 k of n k-bit integers in an (n—2)-private way. This result is tight as there are protocols for this problem that use exactly this number of random bits.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesStaff View
ISSN: 1432-1378Keywords: Secret sharing scheme ; Graph access structure ; Linear programmingSource: Springer Online Journal Archives 1860-2000Topics: Computer ScienceNotes: Abstract In this paper we continue a study of secret sharing schemes for-access structures based on graphs. Given a graph G, we require that a subset of participants can compute a secret key if they contain an edge of G; otherwise, they can obtain no information regarding the key. We study the information rate of such schemes, which measures how much information in being distributed as shares compared with the size of the secret key, and the average information rate, which is the ratio between the secret size and the arithmetic mean of the size of the shares. We give both upper and lower bounds on the optimal information rate and average information rate that can be obtained. Upper bounds arise by applying entropy arguments due to Capocelli et al. [15]. Lower bounds come from constructions that are based on graph decompositions. Application of these constructions requires solving a particular linear programming problem. We prove some general results concerning the information rate and average information rate for paths, cycles, and trees. Also, we study the 30 (connected) graphs on at most five vertices, obtaining exact values for the optimal information rate in 26 of the 30 cases, and for the optimal average information rate in 28 of the 30 cases.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1573-7586Keywords: Secret Sharing Scheme ; RandomnessSource: Springer Online Journal Archives 1860-2000Topics: Computer ScienceMathematicsNotes: Abstract In this paper we provide upper and lower bounds on the randomness required by the dealer to set up a secret sharing scheme for infinite classes of access structures. Lower bounds are obtained using entropy arguments. Upper bounds derive from a decomposition construction based on combinatorial designs (in particular, t-(v,k,λ) designs). We prove a general result on the randomness needed to construct a scheme for the cycle Cn; when n is odd our bound is tight. We study the access structures on at most four participants and the connected graphs on five vertices, obtaining exact values for the randomness for all them. Also, we analyze the number of random bits required to construct anonymous threshold schemes, giving upper bounds. (Informally, anonymous threshold schemes are schemes in which the secret can be reconstructed without knowledge of which participants hold which shares.)Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 1573-5117Keywords: remobilisation ; nutrients ; organic carbon ; estuarine watersSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract The processes affecting the in-sea diffusion of nutrients at the Tiber River mouth are strongly dependent on seasonal conditions. In summer, during the low-flow period, a two-layer structure is established and it is then possible to detect the occurrence of biological processes in the lower layer, at the sediment level. During these conditions, the mean concentrations of dissolved organic carbon, inorganic phosphorus and nitrogen increase in the lower saline layer above the theoretical dilution values and, in some cases, the concentrations are double those in the upper layer. During high flow periods, mixing between the river and sea water occurs in the coastal area away from the mouth, with the transport of pollutants being affected mainly by physico-chemical processes. This paper reports the results of surveys of the distribution of soluble and particulate nutrients in the Tiber River estuary, as a function of salinity. The role of biological regeneration processes is inferred from a comparison of the different behaviour of the pollutants in summer and winter.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1590-3478Keywords: Amnesia ; conditioning ; procedural memorySource: Springer Online Journal Archives 1860-2000Topics: MedicineDescription / Table of Contents: Sommario Gli autori descrivono uno studio su caso singolo di evitamento condizionato in un grave amnesico affetto da lesioni ischemiche cerebrali bilaterali. Per il condizionamento venne usato un labirinto a quattro vie ed il paziente riceveva uno stimolo avversativo ogni volta che con uno stilo percorreva una delle vie collegata a un generatore di schock elettrici. Attraverso un disegno sperimentale A-B-A è stato possibile dimostrare come il paziente imparò ad evitare la via connessa allo shock elettrico pur senza averne nessuna consapevolezza. L'esperimento rappresenta una ulteriore conferma che nei soggetti amnesici il condizionamento costituisce una delle capacità di apprendimento residue. È ipotizzabile che differenti sistemi neurali siano interessati nei processi di condizionamento.Notes: Abstract We present a single case study of avoidance conditioning in a seriously amnesic patient with bilateral ischemic lesions of the brain. A four-path maze was used for conditioning. The procedure consisted in an aversive stimulus that the patient received every time he traced one of the four maze-paths connected to an electric shock generator with a stylus. Using a single case experimental design A-B-A, we found that the patient learned to avoid the path connected to the electric shock, although he never showed awareness of this. Our study confirms once again that conditioning is one of the residual learning capabilities in amnesic patients. Different neural systems are probably involved in conditioning processes.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesStaff View
ISSN: 1590-3478Keywords: Inferior altitudinal hemianopia ; ischemic optic neuropathySource: Springer Online Journal Archives 1860-2000Topics: MedicineDescription / Table of Contents: Sommario Vierte descritto il caso di un paziente di 60 anni che presentò improvvisamente una emianopsia altitudinale inferiore, bilaterale, omonima e perfettamente simmetrica. I reperti oftalmoscopici e fluoroangiografici erano tipici per una diagnosi di neuropatia ottica ischemica anteriore. Tale malattia di solito inizia in un occhio e tende tipicamente al coinvolgimento dell'altro occhio in un 'elevata percentuale di casi con un intervallo variabile (da alcuni giorni ad alcuni anni). Un'insorgenza bilaterale e simultanea, come nel caso qui riportato è un evento eccezionalmente raro, soprattutto se si considera la simmetricità dei difetti campimetrici che avrebbe potuto suggerire una localizzazione post-chiasmatica della lesione.Notes: Abstract A sixty-year-old patient developed a bilateral symmetrical inferior altitudinal hemianopia in the span of an hour. The ophthalmoscopic and fluorescein angiographic findings were typical of anterior ischemic optic neuropathy (AION). This disease usually begins in one eye and as rule involves the fellow eye after an interval of days or years. Simultaneous bilateral onset of AION in a patient is very rare although not unknown. This case suggests that symmetrical and simultaneous bilateral defects of visual fields may be due to a prechiasmal lesion of the visual pathways.Type of Medium: Electronic ResourceURL: